vegetarianism in sport

Vegetarianism in sport



  1. What are vegetarian diets?
  2. Is a plant-based diet safe for an athlete?
  3. Danger 1 – Complete protein deficiency
  4. Danger 2 – Vitamin deficiency
  5. Danger 3 - Microelement deficiency
  6. Danger 4 – Development of anaemia
  7. Danger 5 – No source of polyunsaturated fatty acids, EPA and DHA
  8. Danger 6 – No source of creatine
  9. Danger 7 – Low energy supply and menstrual disorders
  10. Danger 8 – Gastrointestinal disorders
  11. Organisational problems
  12. Conclusion

In recent years, diets limiting or excluding the consumption of meat, fish and animal-derived products have been attracting more and more interest. With a growing interest in vegetarian diets, there is also a growing group of athletes who notice their potential benefits and consider vegetarianism as a nutrition model for themselves. If you are one of them or you use a meatless diet, this article is just for you! Read it to learn what you should pay attention to while composing your vegetarian meals, and what errors you should avoid in order not to diminish your exercise capacity. A well-balanced vegetarian diet may be healthy and safe, allowing productive workouts and fast post-exercise recovery; however, its use in practice may prove not to be easy. Most certainly, it will require solid knowledge and deep involvement on your part, so that you could ensure supply of all essential nutrients!

What are vegetarian diets?

Vegetarian diets involve deliberate limitation or total elimination of meat or animal-derived products (such as dairy, eggs, or honey) from the menu. Before we proceed to discuss potential dangers of using vegetarian diets, you must know that there are several varieties of them, depending on the elimination of specific animal-derived product. Consequently, the use of particular types of vegetarian diets may be associated with a risk of deficiency of particular nutrients.

The table below presents a division of these diets into two major categories: pseudo-vegetarian diets (limiting meat) and vegetarian diets (eliminating meat) with a more detailed classification, specifying the products eliminated and indicating potential deficiencies.

Classification  Exclusions  Possible deficiencies
Pseudo-vegetarian diets  Flexitarianism  Limited amount of meat  Depending on the amount of consumed meat and fish, possible vitamin B12 and iron deficiency 
Pescetarianism  Elimination of meat, with no limitation of fish consumption  Depending on the amount of consumed fish, possible vitamin B12 and iron deficiency 
Vegetarian diets  Lacto-ovo vegetarianism  Elimination of meat and fish  Vitamin B12, omega-3 acids (EPA and DHA), iron, creatine 
Lacto-vegetarianism  Elimination of meat, fish and eggs  Vitamin B12, omega-3 acids (EPA and DHA)), iron, creatine 
Ovo-vegetarianism  Elimination of meat, fish and dairy  Vitamin B12, calcium, omega-3 acids (EPA and DHA)), iron, creatine 
Veganism  Elimination of all animal-derived products, including meat, fish, eggs and dairy  Protein, vitamins B2 and B12, calcium, omega-3 acids (EPA and DHA), iron, creatine 

Table 1. Types of vegetarian diets, from the least to the most restrictive, indicating exclusions and potential nutritional deficiencies. On each of the above-mentioned diets, you may also be exposed to vitamin D3, iodine and selenium deficiencies - nutrients that are deficient in the general population.

Is a plant-based diet safe for an athlete?

It is important to emphasize that current state knowledge confirms that diets limiting or eliminating animal-derived products are possible to balance and safe for use at any stage of life. However, as an athlete using this nutritional model, you must pay particular attention to adequate supply of nutrients in order not to diminish your capacity and, consequently, your sports results and achievements. The key to success is appropriate meal planning and supplementation, preferably in cooperation with a sports dietician. You must also remember that using a nutrition model based on a vegetarian or vegan diet, you may encounter numerous difficulties related to adequate supply of energy or particular nutrients. For this reason, in some instances, despite your best efforts, the implementation of a vegetarian diet, and particularly vegan diet, may turn out to be difficult, and sometimes almost impossible.

Danger 1 – Complete protein deficiency

In an athlete's diet, protein plays a crucial role. It is essential not only for the construction and recovery of muscles and connective tissue (constituting e.g. joints, tendons and ligaments) after a workout, but also takes part in metabolic and regulatory processes. Proteins also play a crucial role in the function of the immune system, enabling an effective immune response of the body to various pathogens and other foreign agents. Unfortunately, if you use an elimination diet, intake of a good quality protein in an adequate amount may be difficult. The biggest problems that you may encounter when deciding on sources of plant protein are: ensuring adequate total supply of protein, its amino acid composition and digestibility. Let us have a closer look at them.

Protein supply
You do realise that meat is not the only source of protein in human diet, and, when choosing such products as eggs, dairy, legumes (bean, pea, broad bean, soybean) and their preparations, nuts or cereal seeds, you are able to supply and adequate amount of protein. In spite of this, however, certain athletes may have a problem with intake of an adequate amount of protein while on a vegetarian, and especially vegan, diet. This will particularly refer to athletes practising strength sports with a protein demand exceeding 2 g/kg body weight/day, as well as to tall athletes, e.g. basketball players, volleyball players and/or those with a substantial body weight, often exceeding 100 kg. It is easy to calculate that their daily protein demandcan exceed 200g/day, which amounts to 40-50 g protein per meal.

Amino acid composition
Proteins are composed of a set of 20 building units called amino acids. Complete protein is such protein that contains all essential amino acids, which additionally occur in specific proportions. Hen’s egg protein, called ovalbumin, is considered a protein standard. It contains all non-essential amino acids, which may be synthesized in the body, and essential amino acids, i.e. such that cannot be produced by the body itself and must be supplied with food. In the table below, you can find a list of all 20 protein amino acids, with a division into essential, conditionally essential (see description) and non-essential amino acids, with their common three-letter abbreviations.

Lp. Essential Amino Acids (EAA) Lp. Conditionally Essential Amino Acids (CEAA) Lp. Non-Essential Amino Acids (NEAA)
1 Phenylalanine, Phe 9 Arginine Arg 17 Alanine, Ala
2 Leucine, Leu,BCAA 10 Cysteine, Cys 18 Asparagine, Asn
3 Lysine, Lys 11 Glycine, Gly 19 Aspartic Acid, Asp
4 Isoleucine, Ile,BCAA 12 Glutamine, Gln 20 Glutamic Acid, Glu
5 Methionine, Met 13 Histidine His
6 Threonine, Thr 14 Proline, Pro
7 Tryptophan, Trp 15 Serine, Ser
8 Valine, Val,BCAA 16 Tyrosine, Tyr

Table 2. There are 20 protein amino acids (included in proteins) which may be divided into essential, i.e. such that must be supplied with food, and non-essential, which can be synthesized by the body itself in the event of their insufficient supply with food. These terms refer to the needs of the body under specific conditions. That is why, some amino acids are classified as semi-essential [1], which means that the amount of these amino acids synthesized by the body is sufficient for a healthy, adult person, but not for a developing body of a child or teenager [2], or in the case of diseases, injuries, persons building their muscle mass or in the case of an intense physical effort [3, 4, 5].

In contrast to complete proteins, plant proteins are often called incomplete proteins or deficient proteins. This means that they do not contain all essential amino acids in proportions sufficient to meet the needs of the body. They often lack one or more essential amino acids which the body is not able to synthesize and which must be supplied with food. Such amino acids, whose amount is too low in relation to the standard protein, are called limiting amino acids. What is important is the fact that if a given protein contains even one limiting amino acid, such protein may not be fully used by the body.

Although a vegetarian diet, due to consumption of eggs and dairy containing complete animal protein of good digestibility does not normally pose a problem in providing an adequate amino acid composition, in the case of a vegan diet, the level of difficulty in composing a balanced meal is highly increased. One of the problems is that a vegan diet supplies an inadequate amount of leucine, one of three branched-chain amino acids, which represents a limiting amino acid. Leucine plays a crucial role in athletes, participating in muscle protein synthesis (MPS). Ensuring adequate leucine supply is especially important in the period of building muscle mass, e.g. in bodybuilders, and for muscle recovery, and it particularly concerns athletes with a high number and volume of workouts [1].

It is also necessary to mention here that deficiency of even one amino acid in food may also result in a negative nitrogen balance, when more bodily protein is degraded than biosynthesized. As a result, your body excretes more nitrogen than it receives with food. This state, if maintained for a longer period of time, may lead to a series of negative consequences to your body, especially loss of muscle mass, decrease in physical performance, higher risk of injury, reduced immunity and longer recovery after exercise.

Another difficulty is the fact that plant protein is characterised by lower digestibility as compared to animal sources of protein. This is caused by the presence in plants of dietary fibre and anti-nutrients, i.e. compounds that hinder or significantly restrict the use of nutrientsin food - in this case, of proteins. Examples include inhibitors of digestive enzymes such as trypsin and chymotrypsin contained in wheat, legumes and in potatoes.

How can I meet the need of protein being a vegetarian?
So, how to address problems related to the use of plant sources of protein? Firstly, to ensure an adequate level of protein supply, supplementation with an appropriate preparation may turn out to be necessary. If you are a vegetarian, you may reach for protein powder supplements based on milk protein, especially whey protein concentrate (WPC), whey protein isolate (WPI) and casein (Ca, C), or to supplements containing pure hen’s egg protein in the form of powder. In the case of a plant-based diet, you should think about products containing vegan protein, such as soy protein or plant protein mixtures, e.g. pea protein and rice protein. They may also include hemp protein, buckwheat protein, mustard protein or protein derived from chia seeds.


Photo 1. Protein supplements based on the mixture of pea and rice protein are an alternative to traditional animal-derived protein supplements, such as whey protein or casein.

Secondly, in order to achieve an adequate amino acid profile, try to combine products which complement one another with regard to a missing amino acid, e.g. cereal products in which limiting amino acids are lysine and threonine can be combined with legumes, such as beans, lentils, chickpeas, for which a limiting amino acid can be methionine. Thus, both groups of products will be complementary products, which means that when you combine them, you can supplement missing amino acids. You might also get interested in soybean and its products, e.g. soy chops, soy granules, tofu (popular ingredient used in the Asian cuisine with a consistency similar to quark cheese), tempeh (product originating from Indonesia and produced from fermented soybean and other legumes), which are one of few plant sources of protein containing a complete amino acid profile. A popular ingredient in the vegan and vegetarian cuisine is also seitan, a product obtained by removing starch from wheat flour, leaving an elastic mass consisting of gluten protein (gluten). Due to its neutral taste, allowing capturing various flavours and spices, and a characteristic, meat-like consistency, it is a good meat substitute. For subjects suffering from coeliac disease who want to use a vegan diet, a valuable source of plant proteins is also quinoa (pronounced /kiːnwɑː/), whose seeds contain all essential amino acids, at the same time being naturally gluten-free.


Photo 2. Seitan, i.e. prepared wheat gluten is a common meat supplement in a vegetarian and vegan cuisine.

Thirdly, appropriate methods of plant-based product processing, such as: fermentation, shooting, wetting, boiling, can increase digestibility of proteins contained therein [6].

Danger 2 – Vitamin deficiency

Vitamin D3 deficiency
Being on a vegetarian or vegan diet, as well as when you use a conventional diet, you are not able to cover your need for vitamin D3 with food because a key role in obtaining this vitamin is played by skin synthesis. Remember to expose your body to sunlight for at least 15 minutes a day in the period between April and October from 10:00 to 15:00. In other months or if exposure to sun is not possible, be sure to remember about vitamin D3 supplementation. You can read about recommendations for the supplementation of this vitamin in a separate article on our website.

Vitamin B2 (riboflavin) deficiency
The main food source of riboflavin (vitamin B2) is meat, but it can also be found in large quantities in dairy products and eggs. If you eliminate these products from your diet, you must ensure that your meals include wholemeal cereal products, such as pasta, bread, millet groats, or buckwheat groats, and also legumes, e.g. beans, or soybeans, and dark green leafy vegetables, such as e.g. kale. It is also important that your vegetarian diet contain significant amounts of unprocessed products, since they are the ones with their higher content. You must also remember that vitamin B2 is sensitive to light, so plant products may lose it while being stored under inappropriate conditions.

Vitamin B12 (cobalamin) deficiency
The only food source of vitamin B12 are animal products: meat (especially beef liver, kidneys), fish (especially pike), milk products and eggs. Unfortunately, no plant product is a source of vitamin B12, and its small amount in plants is usually caused by contamination with bacteria, e.g. those developed in the process of fermentation. Therefore, if you limit meat in your diet using pseudo-vegetarian diets, you should consider supplementation of this vitamin. In the case of meatless diets, Vitamin B12 supplementation is absolutely necessary! Remember that vitamin B12 deficiency contributes not only to reducing exercise capacity, but also to the development of serious diseases, such as megaloblastic anaemia or nerve damage.

Danger 3 - Microelement deficiency

Iron deficiency
Perhaps you know that iron can be present in food in two forms: haem iron (in meat products) and non-haem iron (in other products). Non-haem iron has a much lower bioavailability – only 5-10% is absorbed from the gastrointestinal tract, which translates into much lower possibilities of its use by the body. As a result, a vegetarian diet, especially a vegan diet, increases a risk of iron deficiency, which in turn may lead to body weakness, development of anaemia and reduced exercise performance with deterioration of recovery. The problem is of particular concern for menstruating women, as well as athletes practising endurance sports due to their increased demand for this microelement. When composing your meals, you must also pay attention to the fact that plant sources of iron additionally contain a lot of anti-nutrients which make its absorption from food difficult. These are for example phytates contained in legumes, polyphenols present in coffee or tea, calcium contained in milk or cheese, or a high amount of dietary fibre. According to some sources, because of low bioavailability and presence of compounds reducing iron absorption from plant products, persons on vegetarian diets should increase iron supply by even 180% in relation to the demand of persons on a conventional diet.

vegan source of iron

Photo 3. Pumpkin seeds, spinach leaves, broccoli, nuts, or tofu, are a good source of iron. But remember that it is non-haem iron, whose bioavailability is relatively low. A good idea would be to combine them with products rich in vitamin C, such as citrus fruit, improving its absorption.

Iodine deficiency
Iodine is one of the most important microelements for normal body function, essential e.g. for the production of thyroid hormones. The main symptoms of iodine deficiency include hypothyroidism, which can limit exercise performance, as well as reduced ability to learn, memorise and associate, and a decreased intelligence quotient (IQ). The European continent has the highest percentage of people consuming too little iodine (about 60%), and everyday food of the Europeans does not provide adequate intake of this element.

Unfortunately, persons on vegetarian diets, especially, a vegan diet, are more exposed to iodine deficiency than those using a conventional diet [1, 7]. This happens not only due to the fact that most plant products contain little iodine. An additional difficulty is that they contain so called goitrogenic substances, which may inhibit iodine absorption or block the production of thyroid hormones. Products rich in goitrogenic substances include cruciferous vegetables (broccoli, cabbage, cauliflower, Brussels sprouts, turnip, cress, kale or radish), legumes (beans, peas, lentils), soybean, sweet potatoes or flax seed. These products may be problematic for persons with existing iodine deficiency or thyroid dysfunction. However, if you regularly monitor your state of health, e.g. by having check-ups of blood thyroid hormones (TSH, T3, T4) and you use a balanced diet, you do not have to worry about their consumption.

A naturals source of iodine is marine fish (e.g. cod, salmon, mackerel and tuna), seafood (e.g. shrimps, mussels, oysters and crabs) and to a lesser degree milk products, especially if animals have received feed supplemented with iodine. A good source of iodine for persons using plant-based diets are popular in Asian cuisine seaweeds, such as wakame, nori (sold as “algae for sushi”), kombu (kelp) or spirulina. You can buy these products in shops with health food, Asian shops or in shops with oriental food. Due to limited availability of sources of iodine for vegetarians, especially vegans, you should also consider the use of iodised salt (containing an enriching additive, e.g. potassium iodine) for cooking and seasoning food, and for preparing preserves. And remember that many types of salt, including popular Himalayan salt, considered a natural product not subject to chemical treatment and without artificial additives, is often not iodised, and its natural content of iodine is very low. This also refers to many types of popular Kłodawa salt, as well as to salt used for industrial purposes. That is why, the best choice for you would be to use traditional rock or evaporated iodised cooking salt.

Selenium deficiency
Selenium is a trace element playing an important role in the human body. It is essential for normal function of thyroid, (participates in the production of thyroid hormones), immune system, it affects muscle efficiency and counteracts oxidative stress. Thus, its deficiency will have a negative effect on exercise capacity. Unfortunately, similarly to iodine, it is a deficient element for people living in Europe, which is caused by its low content in soil. Selenium may be accumulated in muscles, liver, kidneys and other animal tissues, which leads to its cumulation in animal-derived products, such as eggs or milk. Therefore, these products may be a valuable source of selenium. For persons on meatless diets, one of the richest sources of selenium are Brazil nuts. Remember, however, that the content of this microelement will differ depending on cultivation conditions, soil composition and region of origin. If you use a vegetarian diet, especially a vegan diet, you may find it difficult to meet the required selenium supply. In such a situation, it is advisable to have a blood selenium test, consult a sports dietician and consider supplementation of this element.

brasil walnut

Photo 4. Brazil nuts are one of the richest sources of selenium for persons on a vegetarian or vegan diet

Reduced calcium supply
Due to the elimination of the richest source of calcium, i.e. dairy, you should take special care to supply this microelement when on a vegan diet. Low calcium supply can cause muscle weakness, development of osteoporosis, and increased risk of fractures. It is advisable to use dairy substitutes, such as plant drinks and yoghurts, tofu, which are fortified with calcium. Calcium absorption from such products is comparable to absorption of cow’s milk. It should also be mentioned that water, especially highly-mineralised water, can also be a valuable source of this element.

Danger 4 – Development of anaemia

You might have met with a conviction that persons on a vegetarian diet are weak, pale and close to fainting. Such a picture may refer to somebody who, due to lack of a planned diet and dietary errors, have developed anaemia.

Anaemia is a condition when there is insufficient amount of haemoglobin in the body to efficiently transport oxygen to tissues. That is why, persons struggling with anaemia are often weak, have a slower recovery rate, and their workout capacity is much reduced. Anaemia resulting from iron deficiency is called microcytic anaemia and is characterised by a lower number red blood cells (erythrocytes) and their smaller diameter. But if the underlying cause of anaemia is vitamin B12 and B9 (folic acid) deficiency, it is called megaloblastic anaemia. Its underlying cause is abnormal DNA synthesis in bone marrow stem cells, which leads to the production of red blood cells with atypical, enlarged (megaloblastic) cell nuclei.

If your diet is varied and rich in leafy vegetables, cereals and legumes, you do not have to worry about vitamin B9 deficiency, since you are sure to supply its sufficient amount to your body. It is different, however, with regard to the other two elements. Using a vegetarian diet, it is absolutely necessary to supplement vitamin B12, since no plant product is able to supply it. You must also ensure adequate supply and absorption of iron in your diet. Menstruating women, endurance athletes and injured persons should pay special attention to the amount of iron taken.

Danger 5 – No source of polyunsaturated fatty acids, EPA and DHA

Polyunsaturated fatty acids, EPA and DHA, belonging to omega-3 acid family, are a group of nutrients essential for health, which a human body cannot produce in sufficient amounts by itself. Thus, they must be supplied with food. Popular plant products, such as avocado, olives or nuts include many examples providing healthy fats, but none of them is a source of these precious nutrients. One of few plant sources of polyunsaturated omega-3 acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are seaweeds. They are a primary source of these acids for fish and other sea creatures. You can also find supplements based on them on the market, e.g. microalgal oil EPA and DHA facilitate normal function of the cardiovascular system, they can improve cognitive function and exercise performance, have an anti-inflammatory effect and can help in recovery. The main food source of EPA and DHA are fatty marine fish and fish oil, so when you decide on a diet which eliminates these products, you should consider their supplementation[8].


Photo 5. Popular plant products, such as avocado, olives or nuts include many examples providing healthy fats, but none of them is a source of polyunsaturated omega -3 acids: EPA and DHA. Their best source are fatty marine fish and fish oil. When you decide to eliminate these products, it is worth considering their supplementation.

Danger 6 – No source of creatine

Creatine is a natural nonprotein amino acid, which is found primarily in muscles. A human body produces about 1 g of creatine daily, which amounts to 50% of demand. The rest should be supplied with food and/or in the form of adequately selected supplementation. Remember that the only natural source of creatine in a diet are meat products and fish; therefore, if you limit or eliminate them, supplementation is necessary. Literature data show that persons with a low level of creatine in the muscles, including persons on meatless diets, may benefit from supplementation more than those on a conventional diet [9]. Creatine is a well-studied substance, showing an ergogenic effect, i.e. improving exercise performance. An especially positive effect of creatine may be observed by athletes whose exercise is characterised by high intensity and short duration, or repeated intervals (intermittence), e.g. strength sports, football or sprints.


Photo 6. Creatine monohydrate is one of the best studied supplements with an ergogenic effect (improving physical performance, capacity or ability to exercise). If you limit or eliminate meat products and fish in your diet, creatine supplementation will be a necessity.

Danger 7 – Low energy supply and menstrual disorders

Some athletes who use a conventional diet, especially those practising endurance disciplines, may find it difficult to meet their caloric requirement related to very high energy expenditures during workouts. In the case of vegetarians, supplying an adequate amount of energy is more difficult, since plant products are characterised by lower energy density. A vegetarian diet is also based on such products as e.g. legumes, which are characterised by high satiety. Using this nutritional model you may sooner have a feeling of satiety and your appetite may be reduced, despite an inadequate caloric intake from the diet in relation to demand. This may result in weight loss, which is not always a desired effect. Low energy density of foods combined with an early occurrence of the feeling of satiety make it difficult to meet the energy requirement, possibly leading to a chronic caloric deficit. In the case of women, an inadequate energy supply combined with heavy workouts may lead to menstrual disorders, or even to lack of menstruation. If you have too few calories, your body receives a signal to enter a state of energy saving. In this situation, the body does not want to allow pregnancy, since its occurrence would require high energy expenditures. In order to meet the energy requirement in physically active persons, it may be necessary to include energetically dense products in their diet, such as dried fruit, jams, oils, pips, fruit juices or refined cereal products.

Danger 8 – Gastrointestinal disorders

A plant-based diet may increase a risk of gastrointestinal problems, such as diarrhoea, constipation, bloating or abdominal pain. This is related to a high supply of dietary fibre, which may reach 100 g/day, and of products rich in so-called FODMAP, i.e. Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols, e.g. apples, legumes, broccoli, cauliflower, onion, garlic. This issue is especially problematic in endurance athletes, who are exposed to the occurrence of exercise-induced gastrointestinal disorders reducing their performance and workout comfort. They are caused by blood flood changes, since during physical activity blood is primarily supplied to sites working the most (which is related to a reduced blood flow in the gastrointestinal tract), mechanical impulses, like shaking e.g. while jogging, or by the position adopted, e.g. while cycling, which affect the gastrointestinal function. If you observe gastric problems during a workout, it is important to adequately compose your meals, paying special attention to peri-workout nutrition before a workout and after a workout. Reach for tried products and those you tolerate well. Also pay attention to the form and method of meal treatment. Before a workout, it is a good idea to choose meals in a liquid form, e.g. cocktails. Instead of fried, heavy foods, choose foods boiled in water or steamed.

Organisational problems

Considering the issue of difficulties to be encountered when using a vegetarian diet, we should mention situations when a possibility of preparing your own meals is limited, e.g. on trips, during events or at sports centres. Unfortunately, many places are still not adapted for adequate preparation of meals used in elimination diets. Lack of training of the kitchen staff with regard to appropriate culinary processing, substitutes or macroelement balancing may result in your diet at that time being deficient, little varied, or at best untasty. You must also account for limited availability of substitutes of some animal products, e.g. tofu, tempeh or plant drinks while being away, especially when you go to small towns or abroad. Always try to have an alternative up your sleeve, which will ensure that even in crisis situation you will be able to adequately nourish your body.


When you decide on a vegetarian diet, you may encounter numerous difficulties in meeting your demand for nutrients and energy. However, thanks to higher awareness and adequate planning, you will be able to correctly balance your diet. Current state of knowledge shows a neutral effect of a vegetarian diet, including a vegan diet, on exercise capacity. Evidence that this nutrition model can go hand in hand with sport is provided by a sprinter Morgan Mitchell, tennis player Venus Williams, ultramarathon runner Scott Jurek, or F1 racing driver Lewis Hamilton. These are examples of people who have been eliminating animal-derived products for many years, but it has never been an obstacle in achieving success in sport.


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after workout eating

Peri-workout nutrition - part 3.
What to eat after a workout?

If you aim at a quick recovery after a workout or competition, waste no time but have a meal reach in absorbable carbohydrates directly after exercise, even if it is not an “ideal” meal. Dumplings with quark, vegetables and compote shown in the picture will be a better choice than most tasty but fatty and stodgy dishes of Poland’s highland cuisine, like pork ribs with toasted potatoes and fried cabbage, sour cabbage soup with smoked meat, or hunter’s stew. Kalatówki PTTK mountain hostel. Photo by Michał Miśta.



  1. Introduction
  2. Nutrition goals after exercise
  3. Fluid and electrolyte replacement
  4. Carbohydrates, insulin and resynthesis of glycogen
  5. Protein after a workout
  6. Fats after exercise
  7. Conclusion

You don’t want your efforts to be wasted. If you don’t supply necessary nutrients to your body after a workout or competition, your recovery, the key to success in sport, may not proceed in the way you would wish. Optimised post-exercise nutrition is especially important when you have several workout units during the day and you want to quickly recover your energy.


Physical exercise is the time when catabolic processes dominate in your body. Muscular activity leading to microinjuries of muscle fibres, depletion of glycogen reserves, increased level of cortisol, called a stress hormone, contributing to fat degradation, protein degradation and mobilisation of body energy reserves, or release of free radicals damaging cell structures, are just a few examples. You must remember that, metabolically, an increase in your fitness takes place after a completed workout and depends not only on its quality and intensity, but also on effective inhibition of catabolic processes, and quick initiation of recovery processes, i.e. making the body enter the state of anabolism. Key factors for an optimal metabolic recovery are adequate intervals between workouts, including a proper amount of sleep and a well-chosen diet.

Nutrition goals after exercise

Nutrition after a workout aims at three basic goals:

  • fluid and electrolyte replacement,
  • resynthesis of liver and muscle glycogen resources,
  • providing the body with a source of amino acids to rebuild damaged muscle fibres.

Each of them is necessary to regenerate your body.

Fluid and electrolyte replacement

You could read about hydration before exercise, signs of dehydration, and strategy of fluid replacement during a workout in two previous parts of our cycle:

You probably know that water, the main blood component, decides not only about supplying oxygen and nutrients to your body cells, but also about effective removal of toxic metabolites, such as urea formed in the process of protein degradation, creatinine, uric acid (product of purine base degradation), substances created after haemoglobin breakdown: bilirubin, urobilinogen and urobilin (main urine pigment) or oxalic acid and its salts (oxalates). Water also provides for your body thermoregulation.

What to drink after a workout?
To restore balance after a workout, you should replace both water and electrolytes. Sodium and chlorine ions (constituting a total of 90% electrolytes lost with sweat), followed by potassium, magnesium and calcium ions, are critical. If your exercise was not very intense or you do not need to recover quickly for the next workout, it would be sufficient to drink medium- or highly-mineralised water, or a good quality “zero calorie” sports drink. However, you need to know that water is a hypotonic drink, meaning that its osmotic pressure is lower than plasma. Therefore, water is characterised by rapid absorption, leading to plasma dilution and increased rate of urine output. If you want rapid hydration and speedy recovery after a workout, isotonic drinks will be a better choice. Interestingly enough, good hydration properties are also found in… skimmed milk. Due to the content of electrolytes (lactose), protein (whey and casein) and many vitamins, milk may fulfil a role of a recovery drink, both after endurance and strength exercise. However, it should not be used by persons with lactose intolerance or those sensitive to milk proteins.

Amount of fluids after a workout
In order to estimate the amount of fluids lost during physical exercise, it would be best to measure the difference in your body weight before and after a workout. After a completed workout, you should gradually replace fluids up to 150% of the lost body weight. It is essential that post-workout hydration be planned over time, providing small amounts of fluids rich in electrolytes, taken every 20 – 30 minutes until large amounts of straw-coloured urine are produced (you can find more information on the technique of hydration self-study based on the observation of urine colour in Part 1 - what to eat before a workout). Remember not to drink the whole amount of water at once, since a rapid increase in blood volume has a diuretic effect and increases a risk of hyponatremia (blood sodium deficit)!

In order to estimate the amount of water lost during physical exercise, it would be best to measure the difference in your body weight before and after a workout. After a completed workout, you should gradually replace fluids up to 150% of the lost body weight.

Carbohydrates, insulin and resynthesis of glycogen

As a result of having a meal rich in absorbable carbohydrates, the blood glucose level rapidly increases, thus leading to release of insulin by the pancreas. This hormone reveals a strong anabolic effect, which means that it stimulates restructuring and repair of tissues in your body, being responsible e.g. for stimulating glucose transport from the bloodstream to muscle and liver cells. The glucose absorbed from cells is then used for glycogen resynthesis. A quick recovery of glycogen reserves is especially important if your exercise is the endurance type, and if you work out more than once a day.

Anabolic “window of opportunity”
When you work out at high frequency and you want a rapid recovery after the workout, do not delay carbohydrate intake after you finish your workout. Within the first 30 - 60 minutes after workout, your muscle cells show an increased permeability for glucose, which is related to translocation of the glucose transporter (GLUT-4) from the cell interior to membrane, leading to a more effective glucose uptake from the bloodstream. This phenomenon ensures higher availability of glucose, a substrate for glycogen resynthesis is cells, resulting in the fastest possible glycogen restoration! After an hour, muscle glycogen resynthesis slows down to about 10 - 30% of the initial value. To put this knowledge into practice, do not delay drinking a glucose-containing isotonic drink, an energetic drink, carbohydrate snack or a meal rich in carbohydrates with a high glycaemic index, trying to consume it right after exercise, especially if you plan subsequent workout units fairly soon. When compiling subsequent meals, use a high-carbohydrate diet, which will result in a complete glycogen resynthesis within 24 hours.

Endurance sports
In order to achieve a maximum glycogen resynthesis in endurance sports, take 8 – 12 g carbohydrates a day per kilogram body weight. A specific amount of carbohydrates, however, depends on the workout intensity and volume. So, what should you eat after an endurance workout?

One workout/day (or less)
If the interval between your workout sessions is long (you work out once a day or less), the most important aspect in glycogen resynthesis is a total intake of carbohydrates during the day. In practice, however, you may increase their proportion in the post-workout meal. It is worth placing importance on complex carbohydrates from conventional food, choosing such products as groats, rice, oat flakes or wholegrain pasta.

More than one workout/day
A different procedure, however, applies to subjects who work out more than once a day, meaning the time to restore glycogen is shortened. In such situations, take 1 - 1.2 g of carbohydrates per kilogram body weight within the first 3 – 5 hours after exercise [4,5]. Place importance of the sources of carbohydrates with a high glycaemic index >70, e.g. dried fruit, white bread, white pasta or white rice. For example, a female athlete with a body mass of 60 kg should have about 60 g of carbohydrates every hour in the first 4 hours after exercise. In practice, such amount of carbohydrates can be found in 8 rice cakes (80 g), 2 fistfuls of dried dates (90 g), 3 glasses of orange juice (600 ml), or 80 g rice. It may also be helpful to ingest caffeine, which increases the rate of carbohydrate absorption from the gastrointestinal tract. A recommended dose is 3 - 6 mg per kilogram body weight [4]. So, if you weigh 60 kg, drinking a double espresso will supply 3 mg of caffeine per kilogram body weight Another helpful strategy to quickly restore muscle glycogen is to combine carbohydrates and protein in your post-workout meal. The addition of protein (0.2 - 0.4 g per kilogram body weight/ h) will increase the rate of muscle glycogen resynthesis, if the intake of carbohydrates is 0.8 g per kilogram body weight. In the event of higher carbohydrate intake, the extra protein will not additionally increase the glycogen resynthesis [4,5].

Strength workout
Resistance training does not normally deplete glycogen reserves to such an extent that would require immediate carbohydrate replacement. According to available studies, normal carbohydrate intake restores the glycogen reserves within 24 hours. Therefore, carbohydrate intake is not so important for a person doing resistance workout less than once a day.

Products rich in carbohydrates, such as wholemeal bread, potatoes, sweet potatoes, pasta, rice, oat flakes, groats, corn or legumes (e.g. chickpeas, lentils or beans) are a good source of carbohydrates, constituting basic fuel for muscles and the nervous system.

Protein after a workout

ZYou have probably heard of an anabolic “window of opportunity”, not only with reference to carbohydrates, but also proteins, according to which a post-workout meal rich in protein should be taken immediately after a finished workout. Recent studies, however, cast doubts on the above indicating that a single training session may increase muscle protein synthesis even to 24 – 48 h [2, 3, 4] and the key factor influencing its effectiveness is a summary protein intake during the whole day. The duration of an increased activity is individual and depends among others on the type of training stimulus. So, although it is not worth delaying carbohydrate intake after exercise, you do not have to hurry to eat a protein-rich meal directly after a finished workout, but you may take time to prepare it at home, and the protein included in the meal will most certainly be used to effectively restore your muscle fibres. From a practical point of view, having a meal 2 hours after workout will be completely sufficient.

Amount of protein
Post-workout meal should include between 0.25 - 0.4 g protein per each kilogram of body weight [2], or, to make it simple, 20 – 40 g protein [3]. In practice, 20 g protein is included in 200 g cottage cheese, 120 g lean quark, 100 g chicken breast or 25 g whey protein isolate. In addition, a post-workout meal should include 700-3000 mg leucine (essential amino acid, which promotes muscle protein synthesis) [3, 4]. High leucine content can be found e.g. in dairy products, including protein powder supplements, meat, fish or eggs [6].

Quality of protein
Considering the issue of the source of protein in your meal, you should also think about the protein quality. By speaking of quality we mean protein digestibility, as well as an amino acid profile, especially the content of essential amino acids, including leucine, which affect its absorption and use by the body. Animal products, such as dairy or meat, thanks to their better digestibility and more beneficial amino acid profile, will better stimulate the muscle protein synthesis than plant products [6]. However, do not completely resign from plant sources of protein, trying to balance meals in such a way as to include both plant and animal protein products.

A growing number of evidence indicates that muscle fibre regeneration, as well as building muscle mass is mostly facilitated by regular protein intake during the day [1, 2]. or this reason, it seems best to eat 4 - 5 regular meals, each of which contains the 20 – 40 g protein. Numerous studies also indicate that the key aspect for muscle recovery and build-up is also the total protein content during the day. Athletes should consume 1.4 - 2 g protein per kilogram body weight/day. In certain cases, these amounts will be even higher [3]. It all depends on individual issues, including the type and number of workouts and the fitness level of your body.

Whey protein supplementation
Although protein supplements are not indispensable elements of a healthy diet, and it is usually possible to cover the protein demand using conventional products, in certain situations an additional use of a protein powder supplement may be very helpful. One of the most widely used supplements in sport is whey protein, characterised by high absorption. It is available in two forms which differ in the production process and composition:

  • WPC - Whey Protein Concentrate containing approximately 80% protein (this amount may differ depending on the manufacturer). It is characterised by a low content of milk fat and lactose.
  • WPI - Whey Protein Isolate undergoes further filtration processes, which help remove most of non-protein components, like fats and lactose. That is why it contains more, almost 90% protein.

What to choose in practice? Both WPC and WPI is characterised by high digestibility, high leucine content and rapid (WPC) and very rapid (WPI) absorption. Thus, both products will be a good choice. The difference is in price (WPCs are cheaper than WPIs) and a lower lactose content in WPI, which may be significant for subjects suffering from lactose intolerance and those with gastrointestinal problems.

BCAA supplementation
BCAA means Branched-Chain Amino Acids, i.e. valine, leucine and isoleucine. The above amino acids are 3 of 10 essential amino acids, i.e. such that must be delivered with food, since your body is not able to produce them by itself. These include the above-mentioned: valine, leucine and isoleucine, as well as phenylalanine, lysine, methionine, threonine and tryptophan and also two relatively exogenous amino acids (needed by the body in certain conditions, especially during growth) - arginine and histidine. As mentioned above, leucine, a component of BCAA, is an amino acid promoting muscle protein synthesis. Logic tells us that BCAA will be an ideal supplement for muscle development and regeneration. However, available studies deny the popular belief of its effectiveness. According to the Australian Institute of Sport, BCAA has been qualified to Group C supplements, i.e. a group of supplements whose effectiveness... has not been confirmed. Therefore, it is not worth using them, and the money saved could be used for providing an optimal protein intake during the day, so as to deliver all essential amino acids at the same time, preferably from natural sources. What it means in practice? If you eat a product rich in complete protein after a workout, you can increase the muscle protein synthesis even twice as much as when you eat BCAA alonesyntezę białek mięśniowych niż spożywając same BCAA [7]!

To ensure an optimal muscle recovery after a workout, 4 - 5 regular meals are recommended, each of which containing 20 – 40 g protein.

Fats after exercise

Although fats are necessary macroelements of a balanced diet, they are not essential in a post-workout meal. Fats ingested directly after exercise may even have a negative effect of slowing down carbohydrate absorption from the gastrointestinal tract. You should also be careful not to use their excessive amounts, especially if you have your post-workout meal in the evening (greasy, stodgy meals lower the quality of sleep, and thus regeneration), and if you care for rapid muscle regeneration before another training session (fat delays gastric emptying, as well as absorption and use of nutrients from the meal). Fats should be included in the next complete meal, so that their daily amount could reach 20-30% energy per 24 hours [4].


The role of carbohydrates and protein in the post-exercise period is best emphasised by an English saying “Carbohydrate is King, Protein is Queen”. Carbohydrate, as King, enables restoration of muscle and liver glycogen reserves, constituting and undisputed priority in post-workout nutrition, especially if you aim at rapid recovery. On the other hand, complete protein, as Queen, is a source of amino acids necessary to rebuild damaged muscle fibres. This saying also emphasizes the importance of balancing carbohydrates and protein, which should be 4:1 in a meal supporting recovery after exercise. Regardless of providing an adequate portion of carbohydrates and protein, make sure that your post-workout meal contains enough vegetables which are a source of many precious nutrients, such as minerals, vitamins or antioxidants. An essential element of a nutritional jigsaw in the post-workout period is to provide adequate body hydration.

Finally, please remember that all the advice presented in our articles is general in nature. There is no one good solution for everybody. Relative proportions and time of consuming particular nutrients or supplements may significantly differ, depending on the body weight, sex, age, type of physical activity, workout goals, potential food intolerance or deficits, and individual needs of your body, or personal preferences. Therefore, if you have any doubts after reading this article, feel free to contact us. Our sports dietician will help you plan an optimal nutrition strategy, select appropriate nutrients adjusting them to your training goals, and will provide you with valuable guidelines, so as to effectively support your recovery, increase exercise performance to reach optimal results during intense workouts.


  1. Schoenfeld BJ, Aragon A, Wilborn C, Urbina SL, Hayward SE, Krieger J. Pre- versus post-exercise protein intake has similar effects on muscular adaptations. PeerJ. 2017 Jan 3;5:e2825. doi: 10.7717/peerj.2825. Erratum in: PeerJ. 2017 Aug 1;5: PMID: 28070459; PMCID: PMC5214805.
  2. Moore DR. Maximizing Post-exercise Anabolism: The Case for Relative Protein Intakes. Front Nutr. 2019 Sep 10;6:147. doi: 10.3389/fnut.2019.00147. PMID: 31552263; PMCID: PMC6746967.
  3. Jäger R, Kerksick CM, Campbell BI, Cribb PJ, Wells SD, Skwiat TM, Purpura M, Ziegenfuss TN, Ferrando AA, Arent SM, Smith-Ryan AE, Stout JR, Arciero PJ, Ormsbee MJ, Taylor LW, Wilborn CD, Kalman DS, Kreider RB, Willoughby DS, Hoffman JR, Krzykowski JL, Antonio J. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017 Jun 20;14:20. doi: 10.1186/s12970-017-0177-8. PMID: 28642676; PMCID: PMC5477153.
  4. Vitale K, Getzin A. Nutrition and Supplement Update for the Endurance Athlete: Review and Recommendations. Nutrients. 2019 Jun 7;11(6):1289. doi: 10.3390/nu11061289. PMID: 31181616; PMCID: PMC6628334.
  5. Alghannam AF, Gonzalez JT, Betts JA. Restoration of Muscle Glycogen and Functional Capacity: Role of Post-Exercise Carbohydrate and Protein Co-Ingestion. Nutrients. 2018 Feb 23;10(2):253. doi: 10.3390/nu10020253. PMID: 29473893; PMCID: PMC5852829.
  6. van Vliet S, Burd NA, van Loon LJ. The Skeletal Muscle Anabolic Response to Plant- versus Animal-Based Protein Consumption. J Nutr. 2015 Sep;145(9):1981-91. doi: 10.3945/jn.114.204305. Epub 2015 Jul 29. PMID: 26224750.
  7. Fuchs CJ, Hermans WJH, Holwerda AM, Smeets JSJ, Senden JM, van Kranenburg J, Gijsen AP, Wodzig WKHW, Schierbeek H, Verdijk LB, van Loon LJC. Branched-chain amino acid and branched-chain ketoacid ingestion increases muscle protein synthesis rates in vivo in older adults: a double-blind, randomized trial. Am J Clin Nutr. 2019 Oct 1;110(4):862-872. doi: 10.1093/ajcn/nqz120. PMID: 31250889; PMCID: PMC6766442.
  8. D. Śliż, A. Mamcarz, Medycyna Stylu Życia, PZWL Wydawnictwo Lekarskie, Warszawa, 2018
  9. A. Bean, Żywienie w sporcie, Zysk i Spółka Wydawnictwo, Poznań 2019
  10. B. Frączek, J. Krzywański, H. Krzysztofiak, Dietetyka sportowa, PZWL Wydawnictwo Lekarskie, Warszawa, 2019
  11. K. Austin, B. Seebohar, Performance Nutrition. Applying the Science of Nutrient Timing, Human Kinetics, 2011
  12. Lauren A. Antonucci, High-Performance nutrition for masters Athletes, Human Kinetics, 2022



Peri-workout nutrition - part 2.
What to eat during a workout?


All you eat or drink during workout or competition will not only have an effect on your ability to exercise and your well-being, but also on the rate of your recovery. In part two of the article, you will learn how to effectively replenish energy substrates in the form of carbohydrates and how to ensure optimal hydration. These two factors, from the perspective of nutrition, have the greatest effect on the improvement in exercise capacity and delay of fatigue.


  1. Fatigue during exercise
  2. Hypoglycaemia – what it is, signs and symptoms, nutrition
  3. Amount of carbohydrates
  4. Carbohydrates during physical activity
  5. Stimulation of the nervous system
  6. Dehydration and overhydration during a workout
  7. Strategy of fluid replacement during physical activity
  8. Drinking during exercise
  9. Fats
  10. Protein and BCAA
  11. Summary – nutrition during physical activity

Fatigue during exercise

Fatigue occurring during physical activity may have various reasons, e.g. damage to muscle fibres, accumulation of metabolites which interfere with the muscle function (lactate, ammonia, hydrogen ions), overheating of the body or physicochemical changes occurring in the central nervous system. However, the key reasons, especially in long-term exercise, are as follows:

  • depletion of body energy resources, both intracellular ones, e.g. glycogen, as well as blood-derived glucose and free fatty acids, whose presence enables continuous energy transformations;
  • Loss of water and electrolytes, rapidly progressing at high ambient temperature and intensive activity.

Let us have a closer look at them.

Hypoglycaemia – what it is, signs and symptoms, nutrition

Hypoglycaemia (also called low blood sugar) is a condition of a decreased blood glucose level below normal (4.0 - 5.5 mmol/L, corresponding to 70 – 100 mg/ 100 mL (dL)). It may occur not only in diabetic patients treated with insulin, but also in healthy, active subjects, especially during long-term exercise. This abnormality was identified in athletes taking part in the Boston marathon in 1923 who, due to increasing fatigue, fell down at the end of the race. As it turned out, those athletes had a decreased glucose level.

Possible hypoglycaemic symptoms include tremor, dizziness, nausea, weakness, reduced concentration and increased anxiety. Since the time of the above-mentioned marathon, numerous studies have confirmed a hypothesis that a supply of carbohydrates during activity protects the body against hypoglycaemia, especially in long-term exercise and depleted glycogen reserves in the muscles and liver.

Applying this strategy makes it easier for the body to maintain a constant blood glucose level, which not only saves muscle glycogen, but also enables reduction in the cortisol level and muscle protein catabolism.

Amount of carbohydrates

Now you probably wonder how much carbohydrates you should take. This primarily depends on the duration of exercise: the longer exercise, the higher demand.

  • Activity lasting 1 - 2.5 h - if you are planning an activity, especially endurance activity which lasts more than an hour, it would be good for your exercise capacity to supply carbohydrates in the amount of 30 - 60 g/h of exercise. These are quite general recommendations and they should be adjusted to the workout intensity and length of a given individual. If the exercise is characterised by low or moderate intensity, the amounts closer to the lower limit will be sufficient. On the other hand, for intense and longer activity (2-2.5 h), the amount of carbohydrates could be increased to about 60 g/h.
  • Activity lasting more than 2.5 h - during endurance exercise lasting more than 2.5 hours, in order to maintain high exercise intensity, you can increase the amount of supplied carbohydrates even to more than 60 g/h. You must remember, however, that bowels have a limited capacity of absorbing glucose; therefore, you should use various sources of carbohydrates, for example glucose and fructose. Such a combination will enable absorption of a higher amount of carbohydrates, since these sugars are absorbed by means of different transporters. To make it easier, use specialist carbohydrate products.

Although an optimal amount of carbohydrates will have a good effect on sports performance, too much of them, i.e. amounts exceeding 90 g/h or such that your body is not accustomed to during exercise, can lead to their accumulation in the digestive tract and occurrence of gastrointestinal disorders. So, it is not always “the more, the better”! If you do endurance sports, it may be important to get your digestive tract accustomed to consumption of higher amounts of carbohydrates during exercise, so called gut training.

dry date fruits

What to eat during a workout? An interesting suggestion would be dried date fruits, a snack highly valued by athletes, which would be ideal for long-term physical exercise.

Carbohydrates during physical activity

Light sources of carbohydrates, with low fibre content are high glycaemic index, would be the best choice during physical activity. You can choose liquid (isotonic drinks), semi-liquid (energy gels) or solid forms of sugar (ripe banana, date fruit bar or dried dates). It is essential to choose such a form that will be tasty and also easy to take on the go. Certain forms may have an advantage over others, e.g. when your activity takes place at a high temperature. If this is the case, the most recommended option is an isotonic drink, which supplies not only carbohydrates, but also fluids and electrolytes. On the other hand, when exercise takes place under cool conditions, solid products, such as a banana or bar, could be more beneficial. You must remember, however, that the form and type of carbohydrates is less significant than the amount supplied.

An interesting fact showing how much nutrition during exercise can be individualised was the famous snack of Adam Małysz: bread roll and a banana. It was an element of a nutritional strategy developed by Professor Jerzy Żołądź, a physiologist of the ski-jumping team. He noticed that the athletes under his care had problems with maintaining concentration and condition during hours-long competitions. The snack he proposed enabled quick supply of a significant amount of energy without prolonged digestion and burden on the alimentary tract, which reduced the probability of gastrointestinal problems. Moreover, the meal was easy to prepare, transport and store.

adam malysz snack

The peri-workout snack proposed by Professor Jerzy Żołądź, bread roll and a banana enabled the ski-jumpers to supply high amounts of energy during training and competitions, without long digestion and burden on the gastrointestinal tract.

Stimulation of the nervous system

During an intense activity, lasting up to an hour, you can also benefit from carbohydrate consumption. In this case, improvement in exercise capacity can be achieved by regular, 5-second mouth rinsing with a carbohydrate solution, which results in the stimulation of oral receptors which, by sending signals to the brain, affect the reward system. Remember that the mechanism is activated in a situation of reduced carbohydrate availability and reduced resources of liver and muscle glycogen. This happens when the workout is performed on an empty stomach or a long time after a meal. From the perspective of the receptor mechanism, it does not matter if you subsequently swallow the drink or spit it out.

Dehydration and overhydration during a workout

A reduced exercise capacity may be related to body dehydration. That is why, aside from carbohydrate replacement during long-term activity, one must also remember to supply appropriate fluids. The risk of dehydration is higher in subjects doing endurance sports and exercising at a high temperature. This is an effect of intense sweating, which is a natural thermoregulatory mechanism. Its pace depends on individual conditions, such as body surface area, humidity and air flow, as well as the temperature difference between skin and the environment.

In the circle of active people, much is talked about the risk of dehydration. It is worth mentioning, however, that both insufficient and excessive fluid consumption during long-term activity is related to reduced performance and a threat to health. If your body weight after exercise is higher than that recorded before the activity, you probably took too much fluids! Excess fluids may lead to a drop in plasma sodium level, so called hyponatremia. Its mild form does not normally cause any noticeable symptoms, but larger deficits result in muscle spasms and weakness, impaired nerve conduction, as well as nausea and syncope. In extreme cases, it may even be fatal!

Strategy of fluid replacement during physical activity

How important it is to keep balance between lost and supplied water may be illustrated by the fact that dehydration of 2% body weight can significantly reduce your exercise capacity, while a 3% loss is considered critical, resulting for example in damage to thermoregulatory mechanisms. When you exercise at high intensity, during heat, or you sweat a lot, the risk of dehydration is significant. In such case, it is worth considering an individualised hydration strategy. It requires individual planning and should be adjusted to the needs resulting from e.g. exercise length and intensity, rate of sweating, or water and electrolyte loss, and atmospheric conditions (air temperature and humidity).

Drinking during exercise

Try to balance the amount of fluids you take in and lose. You can easily check that by calculating a difference in your body weight before and after exercise. Adjust your fluid supply plan, depending on duration of your exercise.

  • Activity lasting up to 1 h - first of all, ensure good hydration before you start your workout, so as to have a bright, straw colour of your urine (hydration index described in part one of the article). During a short physical exercise you can rely on your own sense of thirst, and hydrate your body with hypotonic drinks, e.g. still mineral water. We recommend highly mineralised waters, e.g. Muszynianka, Piwniczanka or Kryniczanka. On the other hand, try to avoid spring water, which flushes minerals out of the body. When performing activities at a high ambient temperature, choose an isotonic drink. Also remember to take in fluids at regular intervals, and avoid drinking too much fluid at a time, since this may increase diuresis.
  • Activity lasting 1 – 2.5 h - a good option would be an isotonic drink, which will provide effective hydration of your body, and will facilitate glucose supply in the amount of 30 - 60/h. Thanks to that, fatigue caused by exercise will appear much later. An advantage of isotonic drinks is also good taste, which additionally encourages their regular use. If your priority is to replenish carbohydrates, for example after long workout at a low ambient temperature, it may be helpful to hydrate your body using a drink with higher carbohydrate content. And vice versa, for activity at a high temperature, when you want to quickly replenish fluids, it is worth considering a drink with lower carbohydrate content.
  • Activity lasting more than 2.5 h – during a long physical exercise of high intensity, for example taking part in a marathon or triathlon, the strategies used to replace fluids, carbohydrates and sodium are of key importance. For this purpose, it is best to use an individual strategy of hydration, tested and optimised under workout conditions. The best choice would be a sports drink supplying an adequate amount of carbohydrates that do not compete for absorption (30-90 g/h), for example a drink containing a mixture of glucose and fructose. Due to a significant loss of electrolytes and a risk of hyponatremia, it is important to pay attention if a drink contains sodium. For the same reason, one should be cautious not to drink amounts causing an increase in the body weight after exercise. Remember that a 1-2% loss of body weight during long-lasting activity is normal, and usually results from the use of endogenous energy substrates.


Although fats have the highest caloric value per gram of all macroelements, they are not a good source of energy during physical exercise. The reason is a long digestive process of fats (which we discussed in the first part of the article). This not only delays access to the energy originating from fats. An additional problem is the fact that fats are accumulated in the stomach for a long time, possibly causing gastrointestinal complaints. You should remember that fatty acid oxidation, so-called β-oxidation, requires higher amounts of oxygen than carbohydrates, and is not possible under anaerobic conditions. A potential source of energy during exercise is medium chain triglyceride (MCT) oil, obtained primarily from palm oil and coconut oil. It contains medium-chain fatty acids which are rapidly digested (without the participation of pancreatic lipase) and absorbed in the bloodstream. MCT oil has its supporters, including people on a ketogenic diet. Unfortunately, hypotheses indicating benefits of the use of MCT oil in sport have not been confirmed by studies, so far. Nonetheless, if you decide to use it, especially as an element of peri-workout nutrition, remember that MCT oil should be taken in small amounts, not only because of its high energy content, but also due to a risk of gastrointestinal complaints.

Protein and BCAA

Long-term exercise, more than 1.5 hour, results in an increased muscle protein catabolism. An addition of amino acids, especially branched-chain amino acids (BCAAs), during exercise, could reduce the intensity of catabolic process leading to protein degradation. BCAA supplementation during training and competitions has become popular among athletes. This trend has been propagated by dietary supplement manufacturers. Unfortunately, there is no reliable scientific evidence to confirm the efficacy of this strategy. In addition, protein or amino acid intake during exercise, especially endurance training, may cause or increase gastrointestinal disorders. Thus, you should not bother your head about protein during exercise. It is better to focus your attention on those strategies of carbohydrate and fluid replacement that are scientifically confirmed.

Summary – nutrition during physical activity

Undoubtedly, fluid and carbohydrate supply during physical activity is highly beneficial, as confirmed by numerous scientific studies. But remember that selection of optimal nutrition and hydration during exercise is empirical and very individual in nature. Due to multiple factors, including also practical issues, such as possible eating and drinking during activity, it is not possible to indicate one, suitable for everybody, model of peri-workout nutrition. It is worth devoting some time to plan and test a suitable strategy, especially if you do endurance sports, or compete under difficult atmospheric conditions.

If you want to learn more about a diet in physical activity and get some practical tips on what to eat and drink before a workout, you are welcome to read the first part of the article, entitled: What to eat before a workout . You can also decide on individual nutrition consultation, during which we will have a closer look at your goals, type and frequency of your exercise, we will analyse your current nutrition model and laboratory test results, and you will be given specific guidelines on what to eat and drink during the workout, so as to make it more effective.



peri-workout nutrition scheme

Peri-workout nutrition - part 1.
What to eat before workout?


To eat, or not to eat? That is the question...that you often ask yourself before your workout. On the one hand, you don’t want to be knocked out by hunger and a rapid drop in energy during workout, but on the other hand, you also don’t want to feel heavy and sluggish. You've also probably heard of people who run on an empty stomach to lose weight faster... What should you choose to achieve the workout results you hope for, or your best performance at competitions, and at the same time maintain your well-being?


  1. The most common mistakes when eating before training
  2. The goals of pre-workout nutrition
  3. Carbohydrates before training
  4. Glycemic index - what is it and how does it translate into training effevtiveness?
  5. Hypoglycemia - what is it, symptoms, how to avoid it?
  6. Pre-workout meal and gastrointestinal discomfort
  7. Pre-workout meal timing
  8. Protein before training
  9. Fats before training - an inexhaustible source of fuel?
  10. Pre-workout hydration
  11. Summary - how and when to eat before training - tips

The most common mistakes when eating before training

To begin with, you need to realize that it takes no less than 2 or 3 hours to digest, absorb and metabolize food. Foods which are difficult to digest, such as fatty meats, mushrooms, legumes (beans, peas, lentils, chickpeas, broad beans), smoked and canned fish (tuna in oil) or cream-based cakes can literally stay in the stomach for hours! Being aware of this will help you avoid two basic mistakes:

1. Avoid products are often very hard on the stomach in your pre-workout meals.
Before exercise, the foods which are difficult to digest should be avoided at all costs in favor of easily digestible (low-fat and moderate-fiber) meals that provide you with a natural energy boost, especially carbohydrates (as we discuss it in more detail below).

2. There is no point in eating a full meal immediately before your workout
Consuming an abundant meal activates the parasympathetic part of your autonomic nervous system, which is responsible for relaxation, rest, increased blood flow through the gastrointestinal tract area, pancreas and liver, higher secretion of saliva, gastric juice, bile, insulin, but also slower heart rate and bronchoconstriction. This will make you feel tired and drowsy soon after the meal. These physiological reactions are exactly the opposite to what you want to achieve during your workout! If you work out immediately after eating a hearty meal, you won’t be able to use up the calories you have just consumed. Obviously, a full belly can be pretty uncomfortable when you exercise.

However, this does not mean that you should skip the pre-workout meal! If your body doesn’t get energy from food, you risk losing your muscle mass, decreased energy levels and poorer performance during the workout! If your goal is to lose weight, you don’t have to exercise with an empty stomach to accomplish this goal! All you need is an energy deficit during the day which will fit your individual needs. According to research, no change in fat loss was observed between individuals who exercised without or after a meal.

A pre-exercise meal that is properly balanced and consumed with the optimal timing will help you achieve better athletic performance, especially if you plan to work out longer.

The goals of pre-workout nutrition

The main goal of your pre-workout nutritional strategy is to stay hydrated, to replenish glycogen in your muscles and liver, and prepare the body for increased demand for energy. It is also important to keep your gastrointestinal comfort.

A proper pre-workout nutrition and hydration strategy is particularly important in the following cases:

  • prolonged physical activity (for workouts that last more than 60 minutes)
  • high-intensity training
  • exertion in high ambient temperature
  • limitations in the supply of energy and fluids during exercise
  • propensity for hypoglycemia
  • a history of gastrointestinal discomforts.

Carbohydrates before training

Carbohydrates are the main source of energy during high-intensity training, both anaerobic and aerobic. Carbohydrates can be quickly used by your body for energy so you can exercise long and hard. Make room for carbohydrates on your plate before the workout, and you will benefit from improved endurance of your muscles and the nervous system, better performance and increased concentration.

If you exercise, eat 1 to 4 grams of carbohydrase per kilogram of body weight 1-4 hours before the workout. Feel free to adapt these recommendations to your individual needs and preferences, and your gastrointestinal function. A diet rich in carbohydrates is especially recommended for endurance sports (running, cycling, triathlon) or those in which the supply of carbohydrate is crucial to maintain high intensity levels of your training (team and racquet sports).

Glycemic index - what is it and how does it translate into training effevtiveness?

Foods rich in carbohydrates differ in how quickly the blood sugar (glucose) levels rise when a particular food is eaten. Glycemic Index (GI) is a rating system of blood glucose increase within 2 hours after consuming a specific amount of a product containing 50 grams of available carbohydrates. The general perception is that simple sugars cause a sudden but short rise in blood glucose levels, while complex carbohydrates provide stable glycemia. This claim is not entirely true. To provide an example, fructose, a simple sugar contained in fruits, causes a gradual rise in blood glucose levels and has a low GI. When choosing your meals, use a table of glycemic indexes (GIs).

Is the GI of pre-workout meals important? According to research, it is more beneficial to choose products with a low glycemic index to perform better during a workout, especially during long-term endurance activities. This applies specifically to the sports activities where you have a limited ability to supply your body with carbohydrates during the exercise. If you can eat snacks when you exercise, meal selection based on the glycemic index has a negligible effect on your performance. However, we do recommend products with low or moderate GI to help your body maintain stable blood glucose levels (euglycemia).

Hypoglycemia - what is it, symptoms, how to avoid it?

Do you sometimes feel a sudden plunge in energy after starting a workout? This can be caused by a sudden drop in blood glucose levels, or hypoglycemia. There are two main factors that can contribute to this condition: a pre-workout meal high in carbohydrates, which leads to excessive insulin release, or the easier uptake of glucose by muscle cells after the start of the workout.

Some people may experience symptoms such as fatigue, decreased concentration and dizziness. These symptoms usually subside after some time and usually do not affect your performance, but they can be unpleasant, especially if you are a beginner, to the point that you may feel discouraged and discontinue your workout.

To avoid hypoglycemia, a slightly reduced intake of carbohydrates before the workout is recommended (about 1 g/kg body weight). You should also choose foods with a low glycemic index, which will promote euglycemia. Try different meal times to find the timing that is best for you. It is generally believed that the risk of hypoglycemia is the highest if you consume a meal rich in carbohydrates 45-75 minutes before your workout. If you are prone to hypoglycemia, try to avoid eating lots of carbohydrates during this time window. Rather, choose a carbohydrate snack that you consume immediately before your workout. You can also eat sugars during the workout – a sports drink is a perfect choice.

Pre-workout meal and gastrointestinal discomfort

Some active people experience gastrointestinal discomforts during or after a workout. Competitive stress can make such discomforts worse. If you experience gastrointestinal problems before during or after a workout, or you are likely to suffer from this condition, limit the amount of fat and fiber in your meal as these nutrients slow down digestion. It is also important to reduce the amount of products rich in FODMAPs, which is an acronym that stands for: Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols, as these nutrients absorb water in the small intestine and ferment in the large intestine, which can exacerbate intestinal discomfort.

Liquid or semi-liquid meals can also remedy this problem. This form of meal will also work well for people who experience stress-related lack of appetite.

Pre-workout meal timing

You now know that you should preferably eat a meal no later than 60 minutes and no earlier than 4 hours before your workout. But which variant is better?

A meal 3-4 hours before the workout – this is the perfect timing for a pre-competition meal, especially if you compete in endurance activities, and for those struggling with gastrointestinal discomforts. You should opt for an easily digestible meal rich in complex carbohydrates with a low glycemic index. Your meal should be solid. If you're facing intense exertion during a competition or if you struggle with gastrointestinal discomforts, reduce the content of dietary fiber in your meal. For example, you can choose basmati rice as a source of carbohydrates. If you plan to exercise for more than 90 minutes, eat an additional carbohydrate snack (a ripe banana, dried fruit or s sports drink) within 30 minutes before your workout.

A meal 2 hours before the workout – this is the best option in the majority of cases, especially if you train regularly. Your meal should preferably be composed of complex carbohydrates and simple carbohydrates in a 1:1 ratio. Reduce the amount of fiber, particularly if you plan to have an intense workout or when you are concerned about possible gastrointestinal discomforts. Your meal should be solid or semi-solid. We recommend a rice meal or an oat meal with an addition of some fresh fruit.

A meal 1 hour before the workout – unless you have the time to eat your meal earlier, this is the last moment for a balanced meal. Your meal should be preferably liquid or semi-liquid and low in food fiber – a smoothie or shake will be a perfect choice. Avoid fiber-rich foods, such as whole-grain cereal products, which prolong the digestion. You should opt for simple sugars, such as fruit.

Protein before training

High-intensity resistance and endurance training increases the secretion of creatine kinase, which is associated with increased muscle catabolism. To protect muscle fibers, it is recommended to consume 0.3 grams of protein per kilogram of body weight no later than 60 minutes before the workout, as long as this amount of protein is well tolerated by your digestive tract. The supply of proteins reduces muscle damage and soreness. Protein should provide your body with all essential amino acids, in the correct proportions, and the best choice is to eat lean meat, fish, eggs, dairy or soy. Vegans can get the essential amino acids from foods, by combining several sources of protein in one meal, such as legumes and cereals.

Fats before training - an inexhaustible source of fuel?

In general, fats are not the best choice for your pre-workout meal as it takes a long time to digest them (as mentioned above); however, obtaining energy from fat oxidation may be an option for some people practicing endurance sports. This is especially true for ultra-endurance exercise. During long but low-intensity exercise (<70% VO2max), the process of fatty acid oxidation prevails, and if you switch your body to get energy from fats, you may be able to extend your workout. Obviously, this does not apply to a single meal, but rather your diet as a whole as your body needs to learn how to use fats for energy. You should pay special attention to products such as avocados, nuts, olive oil, eggs or fatty fish. With a high-fat diet, your body finds it easier to adapt to exercise that continues for a very long time. However, limited exercise intensity is the price you have to pay when choosing a high-fat diet. Some people will improve their performance on a high-fat diet, but for most people, this type of nutrition will be an obstacle rather than a facilitator in boosting their performance. For high-intensity training, preferably choose a high-carb diet.


Pre-workout hydration

You can stay properly hydrated by drinking water and other fluids contained in food. There is plenty of water in fruit and vegetables. If you eat wholesome meals, make room for fruit and vegetables in your diet and hydrate your body regularly throughout the day, you should be sufficiently hydrated before the workout.

However, there are times when the risk of dehydration during workout increases significantly, in which case a proper pre-workout hydration strategy is very important for your well-being, health and performance. Take extra care when:

  • you have no or only limited ability to drink fluids during your workout to replace fluid loss from sweating,
  • if you are sweating profusely, most often when it is hot.

In these cases, rely on a specific hydration strategy and monitor your hydration. You may use this plan to replenish your body fluids:

4 hours before workout – drink 5-7 ml of fluids per kilogram of body weight.

2 hours before workout – drink 5 ml of fluids per kilogram of body weight, especially if you feel thirsty or if your urine becomes darker.

Directly before your workout – drink additional 300-400 ml of fluids.

To make sure that you start your workout properly hydrated, pay attention to the following:

  • thirst
  • urine color and volume
  • urine specific gravity (if possible)

Based on these factors, you can easily find out whether you have consumed the right amount of fluids or if perhaps you need more. If your urine becomes darker, if you urinate less, or if your urine has a higher specific gravity (> 1.035 g/l) or you simply feel thirsty, make sure to drink more fluids. Hydrate yourself with medium or high mineralized water before the workout. To rehydrate your body quickly, grab an isotonic drink, whose osmolality is similar to that of the fluids of the body, and is quickly absorbed in the intestines and effectively hydrates the body.

You can easily estimate your level of hydration based on the color and volume of your urine. This is especially important during hot weather and high-intensity workout and/or high ambient temperatures. Straw-colored or slightly yellow urine combined with a large volume of urine indicate normal body hydration. The darker your urine, and the less you urinate, the more dehydrated you are.


Summary - how and when to eat before training - tips

Let's answer the question: to eat or not to eat before training? We hope that the answer is simple – you should definitely eat your pre-workout meal. However, the timing, consistency and composition of your pre-workout meal are highly individual. In order to develop an optimal nutritional strategy, try testing different options and see what works best for you. You can also consult a sports nutritionist to help you choose the optimal nutritional strategy tailored to the type, time and intensity of your physical activity, in addition to your individual preferences.





carbohydrate loading

Carbohydrate loading, or how to outsmart fatigue?

carbohydrate loading


Endurance sports, such as marathon, cycling, triathlon, cross-country running, long distance swimming, kayaking, rowing or cross-country skiing are highly popular. These activities require selection of an adequate type of training and complex preparation. One of its pillars is development of an individualised nutrition strategy, which not only enables the body to handle intense training, but also ensures optimal regeneration, prevents gastrointestinal problems or helps maintain well-being. Adequately selected nutrition, especially in the period around the event, will also have a great impact on performance.


  1. Wall
  2. Energy for working muscles
  3. Phosphocreatine
  4. Glycogen
  5. Use of glycogen in various types of muscle fibres
  6. Two phases of glycogen resythesis
  7. Glycogen hypercompensation
  8. Carbohydrate loading - what it is?
  9. Classsic model of carbohydrate loading
  10. Contemporary model of carbohydrate loading
  11. Carbohydrate loading - when and for whom?
  12. Carbohydrate loading in non-endurance disciplines
  13. Carbohydrate loading and sex
  14. Carbohydrate loading - use in practice
  15. Carbohydrate loading in advance
  16. Do not test anything during competition!


Watching reports of athletes approaching the finish of a marathon we often see moving scenes, when staggering athletes unexpectedly fall down. With no strength to continue the race, they cover the last meters on all fours, and cross the finish line with the utmost effort. This phenomenon, manifested as extreme fatigue and sudden energy cut-off, accompanied by slowing the pace during exercise, is defined as “hitting the wall”, “bonking” or “blowing up”. The term originates from cycling, but it equally refers to other endurance sports. The causes of “hitting the wall” are complex, but one of the most important causes is undoubtedly depletion of body energy reserves.

Energy for working muscles

Adenosine triphosphate, known as ATP, is a direct substrate supplying energy to the working muscles, and playing a role of a universal energy carrier. ATP reserve accumulated in the muscle cell is very small and allows for only a few contractions. In spite of this, even during intense exercise, its resources are depleted only by 20% to 30% of the initial content. The body does not allow depletion of ATP resources, since that would cause permanent connection of actin and myosin threads, i.e. protein filaments, whose physical interaction enables the function of a muscle cell (myocyte). This condition occurs after life processes are stopped, with resulting rigor mortis.

However, let us return to ATP. As already mentioned, its resource in the cell is very limited; therefore, it must be constantly regenerated. This process happens constantly with surprising efficacy: a working muscle cell recovers its all ATP pool in less than a minute, and the total amount of ATP undergoing recirculation in 24 hours is approximately equal to the body weight! This effective ATP regeneration certainly requires significant amounts of energy. In cell muscles, this energy is derived in the first place from another high-energy compound, called phosphocreatine.


The phosphocreatine supply in the muscle cells enables maintenance of high rate of ATP regeneration within several seconds of the start of exercise. Although this is a key energy source for athletes practising disciplines where the energy demand is immediate and short-term, e.g. weight-lifters, in the case of runners, the phosphocreatine pool stored in the muscles is sufficient for a 100 metre sprint. In order to continue exercise, the body would have to reach for other energy substrates, which may come from intramuscular sources (endogenous substrates -glycogen and triacylglycerols) and from blood (exogenous substrates, such as glucose, free fatty acids, plasma lipoproteins, ketone bodies or some amino acids). The degree of consumption of particular energy substrates depends on the type of muscle fibres, and on the intensity and duration of exercise. The awareness of their diversity, and the ability of their optimal regeneration is crucial for the selection of an optimal nutrition strategy. This will also affect the effectiveness of the exercise. In the case of endurance sport disciplines, one endogenous substrate is of special importance, i.e.…


Glucose is a basic and very productive source of energy for body cells. Suffice it to say that complete oxidation of one glucose molecule results in the formation of about 30 ATP molecules. For a certain type of cells, such as red blood cells (erythrocytes), glucose is the only available source of energy. Brain and nerve cells are especially sensitive to glucose absence. In the light of the above-mentioned information, it seems surprising that the total amount of circulating glucose of a person with a body weight of 70 kilograms is only 4 grams. This amount corresponds to a flat teaspoon, and its caloric content is only 16 kilocalories.

Glucose cannot be stored in an unchanged form, since its high concentration would disturb the osmotic balance of the cells, causing their damage. For this reason, human body has developed a complex system based on e.g. antagonistic activity of two hormones – insulin and glucagon, which maintains a relatively constant, standard blood glucose level of 4.0 - 5.5 mmol/l, which corresponds to 70 – 100 mg/ 100 ml (dl), and is defined as euglycaemia in scientific literature. Glucose reserves are stored in the form of osmotically inactive and easy-to-use polymer - a polysaccharide called glycogen. Glycogen is a large molecule, whose core contains protein (glycogenin) surrounded by a high number of branched chains composed of glucose residues (monomers). Their ends form a complex surface of a glycogen particle, which, if necessary, may be quickly degraded, leading to effective release of required amounts of glucose.  A two-dimensional model of a glycogen molecule is presented in the picture below.

A vast majority of glycogen is located in muscle cells - approx. 500 g on average (1% - 2% of the myocyte volume) and hepatic cells - approx. 80 g on average (5% - 6% of the hepatocyte volume), where it forms numerous granules of various sizes dispersed in the cytoplasm and containing different amounts of glucose monomers. The primary role of hepatic glycogen is to maintain constant blood glucose level and to react to the glucose need of the body, as a whole. And muscle glycogen is used only as a local glucose reservoir, available for the needs of a given muscle fibre (constituting a single, multinucleated cell). Due to physiological conditioning, glucose originating from glycogen accumulated in a given muscle fibre cannot be released to blood becoming a source of energy for other cells (or even for the neighbouring muscle fibres). This makes glycogen remain in the muscles for a longer time, and this fact may be used in practice, which will be discussed further in the text.

Muscle glycogen is mainly distributed in three specific regions (compartments) of the cell, in close proximity to the sites where energy supplies are required. It should also be added that glycogen granules are not only “containers” of condensed fuel, like glucose molecules, but have also another significance. To make it simple, they may be said to have a role of “sensors”.  Among other things, glycogen causes transmission of impulse leading to a muscle twitch (release of calcium ions from the sarcoplasmic reticulum) and takes part in the regulation of metabolic pathways related to the processes of exercise adaptation. Moreover, it is a part of the system regulating the intracellular osmotic pressure. Due to this varied role of glycogen, its decreasing resources during exercise may not only disturb energy transformations, but also complex signalling and regulatory processes. From the athlete's point of view, it is important that they impair generation of muscle strength. This is probably why, during highly intense exercise, when the amount of muscle glycogen is much depleted, the body does not decrease its contents below 10% in relation to the initial amount.

Although the amount of glycogen accumulated in the liver and muscles is only 4% of the total energy reserves of the body, it is muscle glycogen that is a basic source of energy for working muscles in the case of exercise of moderate and high intensity.  This results from the involvement (recruitment) of various types of skeletal muscle fibres which have various structural, functional and metabolic characteristics, depending on the type of exercise, which is illustrated in the table below.

Use of glycogen in various types of muscle fibres

Skeletal muscles are built of three types of fibres: type I fibres, i.e. slow-twitch or oxidative, and type IIa and IIx fibres, i.e. fast-twitch, called oxidative-glycolytic and glycolytic fibres, respectively.

During low intensity exercise, even such lasting a few hours, the use of glycogen is relatively low and primarily affects well vascularised and fatigue-resistant type I fibres, which are recruited by the body first. These fibres are naturally poor in glycogen and their chief source of energy is degradation of lipids (triacylglycerols). Lipids are a high-energy form of energy storage, although the process of ATP production therefrom is slower than the production of ATP from glycogen. This fact, combined with low transmission rate of axons innervating type I fibres, translates into their low speed of contraction. That is why they are called slow-twitch fibres. The presented characteristics predispose this type of fibres to be involved in long-term exercise, such as running a marathon or maintaining an extended body position.

Increased burden involves recruitment of glycogen-rich type IIa fibres (oxidative-glycolytic), which may derive energy from both aerobic and anaerobic processes. This results in an increased consumption of glycogen, which is a basic source of energy for these fibres.

In the case of the highest burden, type IIx (glycolytic) fibres are recruited last. They are characterised by “power burst”, typical of sprints or weight-lifting. Their primary source of energy are anaerobic processes. These fibres are able to generate the highest amounts of energy, but they use much of their glycogen reserves for that purpose, rapidly showing fatigue.

It is interesting that in the case of oxidative (type I) fibres, the use of glycogen during intense exercise is reduced with an increased burden. For example, after stopping exercise of very high intensity (due to complete fatigue), there is almost complete glycogen utilisation in type IIx fibres, 70% decrease in the glycogen content in type IIa fibres, and only 25% decline in glycogen in type I fibres.

The proportions in which particular types of muscle fibres occur in a given muscle are genetically determined. Indeed, the proportion of type I fibres in the vastus lateralis muscle (constituting the strongest element of the quadriceps femoris) may range from 5% to 90%! This phenomenon partially accounts for natural predisposition of a given person to a specific type of activity. Therefore, it should not be surprising that athletes prepared in terms of endurance disciplines show a particularly high proportion of type I fibres, while groups of muscles crucial for sprinters and weight-lifers are primarily composed of type IIa and IIx fibres. There is an exception, however, the soleus muscle of the calf, which, regardless of an individual, is characterised by a high content of type I fibres, which is a great example of adaptation to the function it serves.

Traits Types of muscle fibres
Type I
(SO, ST)
Type IIa
Type IIx
Structural Diameter Low High Medium
Vascularity High Medium Low
Fibre colour Red Reddish White
Mitochondrial density High Medium Low
Metabolic Type of metabolism Aerobic Aerobic
and anaerobic
Glycogen content Low High High
Fat (triacylglycerol) content High Medium Low
Myoglobin content High High Low
Functional Order of recruitment 1 2 3
Speed of contraction Low High High
Twitch strength Low Average High
Resistance to fatigue Very high High Low

Two phases of glycogen resynthesis

The recovery of glycogen resources utilised during training takes place in two phases.  A rapid phase of glycogen resynthesis lasts 30-60 minutes after stopping exercise, and is related e.g. to transfer of glucose transporter type 4 proteins (GLU4) on the myocyte mucosa without the participation of insulin, which fosters glucose absorption by the muscle fibre. Glycogen resynthesis is then the fastest. In the subsequent slow (insulin-dependent) phase, glycogen resynthesis is much slowed down to approx. 10 – 30% of the initial value.  Available studies clearly indicate that consuming a portion of absorbable carbohydrates (with high glycaemic index) immediately post training initiates the process of rapid glycogen recovery, lasting for the first 2 hours post exercise. During this time, the so-called “garage door of opportunity” is closed. These data show that if we wish to achieve quick recovery, we must not delay carbohydrate consumption after the training. In this case, the sooner, the better! If we then have a high-carbohydrate diet, i.e. such where carbohydrates constitute at least 70% of the caloric value, a complete glycogen resynthesis occurs within 24 hours.

Glycogen hypercompensation

Continuation of a high-carbohydrate diet in the next 24 – 48 hours significantly increases the glycogen level in relation to pre-exercise content, but one must remember than any muscle injuries suffered during training may prolong this process. If the training volume is significantly reduced during this period, or, even better, complete rest is introduced, this may lead to a phenomenon called hypercompensation (or supercompensation) of glycogen. It has a very practical use in sport.

Carbohydrate loading - what it is?

Carbohydrate loading, also called glycogen loading, is a nutrition strategy to maximise the storage of glycogen in the muscles. This is a simple and well examined method, which is one of the standard elements of pre-event preparation, widely used especially in endurance sports. The optimisation of glycogen resources delays the moment of fatigue and prolongs exercise time at a constant level of intensity even by 20%.

Classic model of carbohydrate loading

The practice of carbohydrate loading dates back to late 60's. A classic model was developed in 1967 by Swedish researchers led by Björn Ahlborg and Jonas Bergström, who conducted histopathological examinations of muscle specimens collected from a group of healthy men. The participants underwent biopsy before and after exercise leading to complete exhaustion. Then, a glycogen content in the collected material was compared. These pioneer studies revealed a positive correlation between the level of muscle glycogen and exercise capacity of athletes, and the loading regimen developed on the basis of these studies have become the most popular method to increase the muscle glycogen for a long time. Let us have a closer look at this.

A classic cycle of carbohydrate loading lasts seven days and begins with a three- or four-day glycogen depletion phase. This is reached by combining a low-carbohydrate diet with training that favours depletion of muscle glycogen. This is followed by the proper three- or four-day carbohydrate loading phase involving the use of high-carbohydrate diet. In order to support glycogen storage, the training volume is reduced in that period, or complete rest is introduced.

This method, however, has serious drawbacks. For athletes practising endurance sports, whose everyday diet is typically rich in carbohydrates, the glycogen depletion phase is particularly burdensome. It could be said that it turns the nutrition upside down. During the depletion phase, there often occur uncomfortable complaints, such as: mood swings, irritation, worse well-being, weakness with drowsiness, headache or gastrointestinal problems. This phase is also associated with an increase in the catabolic cortisol level and higher risk of injury, and the following above-average consumption of carbohydrates in the loading phase exposes the body to a great burden. This naturally raises some concerns as to its use.

Contemporary model of carbohydrate loading

A series of studies conducted a decade later on a group of professional runners by American researchers led by W.M. Sherman revealed that well-trained athletes were able to increase their storage of muscle glycogen without the necessity to use the burdensome depletion phase. The athletes could achieve the same result preceding long-term exercise with a 3-day carbohydrate loading phase, during which they delivered 8-10 g (in extreme cases even 12 g) of carbohydrates per kilogram body weight, resigning from training during that period, or using training of much lower volume. This observation was a kind of breakthrough in the nutrition strategy. Elimination of the unpleasant glycogen depletion phase made the loading method shorter and much easier to use in practice. This model is currently the most popular.

Interestingly, well-trained athletes are able to increase their glycogen storage in the muscles even in one and a half day or two days (36 - 48 hours) only by completely resigning from training in this period and using a diet with an adequate amount of carbohydrates and calories.

Carbohydrate loading - when and for whom?

The strategy of carbohydrate loading will find best use in endurance sports, characterised by a constant level of intensity and duration over 90 minutes. It is especially well explored in such disciplines as marathon or cycling. It will work very well for triathlon and water sports - long-distance swimming, kayaking or rowing. In the case of mountain sports, glycogen loading is beneficial e.g. during cross-country skiing, mountain runs and ski-tours. Potentially, it may also be useful for climbers taking part in social bouldering competition, which are characterised by a long elimination round, lasting typically about 2.5 h -3 h, during which the contestants must climb several dozen boulders. High intensity and interval nature cause high usage of muscle glycogen. What is problematic in climbing sports, however, is the importance of the athlete's body weight. Unfortunately, due to increased amount of glycogen and water bound thereto (1 g glycogen binds 3-4 g water), the body weight increases by 2% - 3%, which may outweigh the benefits of using this nutrition strategy. Nevertheless, it is worth testing under training conditions and assess its effects on an individual basis.

Carbohydrate loading is useful for both amateur and professional athletes, but the higher training level, the larger benefits. It should also be noted that people who do not train regularly are much less capable of storing glycogen than well-trained athletes. This is best illustrated by the fact that the contents of muscle glycogen in trained athletes may reach 900 g, as compared to the above-mentioned mean contents of 500 g.

Glycogen supercompensation, like any other nutrition strategy used in sport, should be tested under training conditions, e.g. for a week weeks before an important event. It is worth consulting a sports dietician, who will help to plan the hypercompensation process with regard to individual needs of a given athlete. Employing this strategy, it is easy to make mistakes which will negate the effort put into this. Such mistake include, e.g.: selection of too fatty, thus stodgy products (French fries, chocolate, pizza), excessive spontaneous physical activity or intense training. They may lead to the utilisation or significant depletion of the accumulated glycogen reserves. Energy deficit is another factor impairing glycogen synthesis. It is a frequent cause of unsuccessful strategies of loading among women.

Carbohydrate loading in non-endurance disciplines

Disciplines that may also show benefits from glycogen hypercompensation include team and racket sports. In these sports, phases of very intense exercise are interchanged with phases of much lower intensity (interval character). Although the time of activity is typically 60 - 90 minutes, they use significant amounts of muscle glycogen. A significant increase in the muscle mass and volume resulting from a higher glycogen content increases the attractiveness of carbohydrate loading also among bodybuilders.

Benefits from using carbohydrate loading in strength sports seem to be limited, although this has not been well explored. As mentioned above, explosive exercise as the main source of energy uses ATP and phosphocreatine; nevertheless, in the case of this type of disciplines, small glycogen reserves may promote disorders in generating muscle strength. While it is worth providing a diet rich in carbohydrates ensuring an adequate glycogen level, it is not necessary to perform glycogen loading.

Carbohydrate loading and sex

Dear ladies, unfortunately, most studies on carbohydrate loading were conducted on men, since the researchers thought that the results would translate into subjects of the other sex. Unfortunately, this was not confirmed by the initial tests. This probably resulted from the fact that women applied energy restrictions which prevented effective storage of glycogen. Subsequent studies conducted with the participation of women confirmed the capacity for glycogen supercompensation provided that a normal-calorie diet was used. Moreover, there are certain observations regarding the effect of the menstrual cycle on the effectiveness of glycogen storage. It appears that supercompensation may be more effective in the luteal phase of the cycle, as compared to the follicular phase.

Carbohydrate loading - use in practice

Carbohydrate loading is performed two or three days before an important event or long-term effort. This is a strategy combining rest or significant reduction of training volume with a diet involving high carbohydrate intake. During this time, the diet should cover the total energy requirement and deliver carbohydrates in the amount of 8 - 10 grams per kilogram body weight (maximum 12). The loading time may be shortened to one and a half day or two days, taking larger amounts of carbohydrates, i.e. approximately 10 -12 grams per kilogram body weight. The shorter regimen will better suit well-trained athletes, who are accustomed to high amounts of carbohydrates in the diet. A diet with high glycaemic index is recommended, since it promotes faster carbohydrate digestion and absorption and, consequently, a more effective glycogen storage. Protein intake should be reduced to a physiological demand (about 1 gram per kilogram body weight), while fats should be reduced to minimum.

A more frequent meal consumption enables a more effective glycogen storage. Even from a practical point of view, it would be very difficult to deliver such high carbohydrate contents only in two or three meals a day. Therefore, five or six meals a day should be planned for this period. Regular consumption of smaller portions gives a lower burden to the gastrointestinal tract, which is a very important factor before the event. It must be mentioned here that high amounts of carbohydrates may cause gastrointestinal problems. Therefore, it is recommended that the diet be light, low-fat, with low fibre content and limited content of high fodmap products.

Fodmap means fermentable oligo-, di- and monosaccharides and polyols, whose digestion in the gastrointestinal tract is limited. Their presence in the small intestine facilitates water accumulation (due to osmotic effect) and favours fermentation in the large intestine. In some people, this may be manifested as bloating, gases, abdominal pain, overflowing, and even diarrhoea or constipation. Popular products high in fodmap content include e.g. garlic, onions, legumes, broccoli, cauliflower, apple, lactose-containing products (especially milk), and popular sweeteners, such as xylitol, erythritol and sorbitol. If there are no health complaints, it is not necessary to completely eliminate fodmap; restriction or careful usage would be enough.

One must also remember that it is impossible to employ the strategy of carbohydrate loading only with the use of healthy (low-processed, wholemeal) products, such as e.g. buckwheat groats, brown pasta and wholemeal rye bread, due to excessive fibre content. As far as these products are a good choice in everyday diet, they constitute excessive burden for the gastrointestinal tract during the loading strategy. Therefore, it is necessary to introduce highly-processed products with high glycaemic index, such as sugar, jam, fruit juices, dry fruits, ice creams, white bread, white pasta, white rice or potatoes. Both the solid and liquid form of carbohydrates has a similar effect on glycogen synthesis; therefore, the issue of consistency is not of much importance. Nevertheless, having regard to digestibility, liquid or half-liquid forms may turn out to be more convenient.

Apparently, the diet during carbohydrate loading is much different from standard nutrition recommendations. It should be noted, however, that this strategy is used only at certain times, exclusively by athletes, and for a very specific purpose of increasing glycogen storage and delaying the moment of fatigue during an important event. This is not a nutrition model that can be used every day.

Carbohydrate loading in advance

Interestingly enough, it is possible to perform carbohydrate loading a few days earlier than specified by a standard two- or three-day protocol and date of the event. This is recommended particularly for athletes who fear gastrointestinal complaints related to stress (preventing ingestion of so much carbohydrates) or a long journey. Glycogen granules accumulated in muscular fibres may be stored for a longer time, which we discussed in the part of the text devoted to glycogen. Then, the strategy is used in advance, so that for another one or two days before an important event a diet with standard carbohydrate content could be introduced, unloading the gastrointestinal tract. This method will be successful provided that the stored glycogen is not used, for example during training or increased spontaneous activity before the event.

Do not test anything during competition!

It should be once again emphasised how important it is to test the strategy of carbohydrate loading under training conditions. Introducing anything new in the week before the event can significantly increase the level of stress and uncertainty. On the other hand, choosing well tested methods allows for more peace of mind resulting from optimisation of the energy availability and lower risk of gastrointestinal disorders.



Nutrition, lifestyle vs. immunity

The immune system is indispensable to our survival. Its primary function is to constantly monitor the organism to identify pathogenic agents (pathogens) and to differentiate between own (host) cells and foreign cells, and also cancer cells. Thanks to its constant activity, the organism is capable of defending itself against infections and diseases.

What we eat affects the functioning of each cell of the human body. Of course, the same applies also the cells forming part of the immune system. Diet is then one of environmental factors that can have a significant impact on our immune system.

It is worth noting that the immune system is not always a salvation to us. It can make errors, e.g. recognise own cells as foreign ones or react in an excessively sensitive way. In such a case, we are dealing with an incorrect immune response, which may manifest itself as allergic, atopic or autoimmune diseases.

Environmental factors affecting the immune system that we can control are:

  • Diet,
  • body nutritional status,
  • circadian rhythm,
  • level of physical activity,
  • stress level,
  • stimulants,
  • medicines.

Thanks to a balanced diet, optimal body weight, sufficient sleep and also its quality, regular physical activity, reducing stress (or learning how to better handle stress situations) and stimulants, we support the functioning of our immune system. At the same time, the efficiency of our own immune system drops if we disregard any of these factors.

Does an immunity-boosting diet exist?

There are many nutritional factors that affect the functioning of our immune system. If I were to respond to this question briefly, a diet with anti-inflammatory properties which boosts our immunity is a diet with an optimal protein intake, rich in vegetables and fruit, such as the Mediterranean diet, vegetarian diet or even vegan diet (with a well-balanced protein intake). We must however take a broader look at different nutritional and lifestyle factors affecting the nutritional status and the condition of the immune system.

Immunity vs. body nutritional status

Overweight and obesity inhibit the functioning of the immune system. Obesity in particular impairs immunity due to an increase in inflammatory mediators. Chronic inflammation accompanying obesity increases the risk of many diseases and infections which impair immunity.

Malnutrition caused by hunger, lack of food or diseases also negatively affects immunity-related functions. The level of immunity impairment depends in this case on the range of nutritional deficiencies and the age of the person suffering malnutrition.


Age is a factor greatly affecting our immunity. From the moment we are born, immunity is shaped by two main factors. These are exposure to external factors and our eating habits. Breastfeeding has a much more positive impact on immunity-related functions and is recommended especially in babies with a family history of immune-related conditions.

The first years of life are a very important period in terms of gaining immunity. Factors affecting the development of the immune system include the presence of pets at home, the existence of siblings, the use of antibiotics, and diet.

With time, the level of immunity in an adult may get reduced. However, in such a case, lowered immunity can be related to nutritional deficiencies. It is especially connected with protein and zinc deficiencies, which have proved to be quite common in elder people. In this situation, intervention aimed at supporting the immune system should focus on supplementing nutritional deficiencies.

Immunity vs. physical activity

Regular and moderate physical activity has great benefits for the organism, including the immune system functions. In turn, intensive physical activity causes a short-term decrease of immunity. According to literature data, such a decrease in immunity persists 3 to 72 hours after finishing intensive workout. It depends in part on carbohydrates intake. In intensive workout routine, immunity can be increased by consuming carbohydrates before and after the workout. Similarly, a low-carb diet will lower the immunity.

Immunity vs. intestines

There is a strong link between intestinal microbiota and immunity. Changes in the intestinal microflora increase the probability of many diseases, including allergy, asthma, autoimmunological diseases and many other disorders. Intestinal microbiota may change as a result of diet and environmental factors.

The factor with a very negative impact on microbiome is antibiotic therapy, thus, taking probiotics during antibiotic treatment is always recommended.

The basic nutritional intervention focussed on strengthening the intestinal microbiome is taking probiotics and prebiotics. The microbiome status is also affected by many lifestyle factors, which must be taken into account when referring to immunity. Such factors include primarily the circadian rhythm, stress level, the level of physical activity, medications taken and consumption of stimulants.

Protein vs. immunity

The deficiency of protein and other amino acids will impair the production of antibodies, and therefore immunity-related functions, in spite of the lack of vitamins and minerals deficiency. At this point, it is worth mentioning vegetarian and vegan diets, which have the greatest benefits for our immune system only on the condition that they provide us with the optimal intake of protein and necessary amino acids. Protein requirement differs depending on the physiological condition, age, health condition, body weight and the level of physical activity. Protein requirement for healthy men and women starting from the age of 19 is 0.9 g/kg of body weight.

Arginine is an exogenous amino acid that is very important for the immune system. According to studies, it has immunostimulating properties. A shorter hospitalisation time was observed in patients receiving arginine supplementation. It is justified by the beneficial effect on the process of regeneration and convalescence. Glutamine and taurine are also believed to have immunomodulating properties.

Antioxidant vitamins: C, E and beta-carotene

Vitamin C deficiency negatively affects the immune system, while no studies exist to prove immunostimulating properties of higher doses. Vitamin C improves immunity only when it is deficient. A good source of vitamin C is rosehip, peppers, blackcurrant and parsley leaves.

Vitamin E dissolves in fats. It is a strong antioxidant and shows immunostimulating properties not only during disease. Deficiencies of this vitamin are rare. They can appear for example in fat malabsorption disorders and coeliac disease. Good sources of vitamin E are vegetable oils, nuts and seeds, such as, e.g. almonds, hazelnuts or sunflower seeds.

Beta-carotene, i.e. provitamin A, is a substance used by the organism to produce vitamin A. Studies confirm the beneficial effect of carotenoids, and beta-carotene in particular, on lowering the risk of cancer and many other chronic diseases. It is, however, worth noting that high doses of vitamin A may produce an immunosuppressive effect, that is reduce the immunity. In the event of a confirmed deficiency, it is worth using supplementation, while for prevention purposes, it is better to include beta-carotene in diet. Good sources of beta-carotene are, among others, carrots, tomatoes, sweet potatoes, peppers, broccoli, spinach.

Vitamin D3

While most people have no problems with antioxidant vitamin deficiencies, the majority of the population suffers from vitamin D deficiency. Vitamin D3 level can be checked by the 25-OH vitamin D test. Exposure to a deficiency of this vitamin, which is of key importance to immunity, increases in the autumn and winter period due to less sunlight. Vitamin D3 deficiency is related to a higher risk of infections and autoimmune diseases. Supplementation of this vitamin is recommended and is safe. Exact recommendations on supplementation can be found in a separate article under this link.


Our diet greatly affects the functioning of the immune system. A well-balanced Mediterranean diet will be very beneficial, as abounds in vegetable and fruit, which are a good source of fibre, vitamins and minerals. It is also important to consume sufficient quantities of protein – standard demand is 0.9-1.5 g/kg of body weight and depends on several factors, such as the physiological condition, age or health condition. With increased activity, the protein requirement can be higher, and it should be individually determined. It is important to maintain the right body weight, because either underweight or overweight and obesity will negatively affect the immune system. Nutritional deficiencies are a special threat. An important vitamin of key importance for immunity and which is deficient in a significant part of the population is vitamin D3. Apart from strictly diet-related factors, the following are key to appropriate immunity: regular circadian rhythm, learning ways to deal with stress, moderate and regular physical activity, elimination of stimulants (smoking tobacco, abuse of alcohol).
When taking medication, especially antibiotics, is necessary, they should be taken strictly in accordance with doctor’s recommendations (duration of therapy, dose), without forgetting about the need to use gastroprotective probiotics.

Recommendations on Vitamin D3 supplementation

Vitamin D3 deficiency is an important public health problem in Poland. It is commonly known that vitamin D3 has beneficial effects not only on regulating calcium and phosphorus metabolism, but also in the prophylaxis and treatment of many diseases.


Three sources of obtaining vitamin D3 by human body are known. The first and most important source of this vitamin is skin synthesis, another source is diet, and then supplementation.

  • Skin synthesis of vitamin D3

This is the most important source of obtaining vitamin D3 by the human body. It is estimated that skin synthesis may cover around 80-90% of daily vitamin D3 requirement. We should add here that in Poland, skin synthesis is effective only in spring and summer (from May to September), between 10 a.m. and 3 p.m., with minimum 15-minute daily exposure to sunlight with uncovered arms and legs. In such conditions, the level of produced vitamin may reach approx. 2,000-4,000 IU. Unfortunately, between October and April, this method of obtaining vitamin D3 has low effectiveness.

  • Diet

Diet is an alternative form of obtaining vitamin D3 by humans. A well-balanced diet may cover approx. 20% of the daily requirement. The most important sources of this vitamin are primarily fish such as wild salmon, herring, and also egg yolk or whole milk. Unfortunately, when skin synthesis of vitamin D3 is insufficient, diet alone is not enough, and optimal supplementation proves to be of key importance.

  • Diet supplementation

For the majority of the population living in Poland, supplementation with vitamin D3 proves to be of key importance in terms of covering the full requirement. The optimum dose of vitamin D3 in the form of a supplement can be determined in two ways. The most important factor in the determination of an individual dose is the knowledge of such parameters as age, body weight, time of the year, sunlight exposure, lifestyle, dietary habits and health condition. Another good way to determine an individual dose is testing the level of 25-OH vitamin D in blood. It is a very good method, however, not always required to select supplementation.


In the majority of cases, where skin synthesis recommendations are met, additional diet supplementation is not necessary, but it is still safe and recommended.

For children between 1 and 10 years of age, the safe recommended dose is 600-1,000 IU/day.

For youth between 11 and 18 years of age, the safe recommended dose is 800-2,000 IU/day.

For adults between 19 and 65 years of age, the safe recommended dose is 800-2,000 IU/day.

For people between 65 and 75 years of age, the safe recommended dose is 800-2,000 IU/day. Such a dose should be taken throughout the year, regardless of skin synthesis.

For people above 75 years of age, the safe recommended dose is 2,000-4,000 IU/day. Such a dose should be taken throughout the year, regardless of skin synthesis.

For pregnant and breastfeeding women, it is recommended that the concentration of 25-OH vitamin D in blood should be on the level of 30-50 mg/ml.

Obese people with BMI above 30 should use double doses recommended for their age group.

Chronically ill people who permanently take medications, suffering from autoimmunological diseases, hormonal disorders, allergies, metabolic or other diseases should always try to adjust their daily dose of vitamin D3 on the basis of 25-OH vitamin D test.


The optimum level of 25-OH vitamin D in blood is 30-50 ng/ml. Depending on the test results, an individual supplementation dose is recommended.

  • 0-10 ng/ml – for such a low level, one should verify whether general recommendations were followed at all. The following initial doses are recommended: for children between 1 and 10 years of age – 3,000-6,000 IU/d, while for people above 10 years of age – 6,000 IU/d. 25-OH vitamin D testing should be repeated after 1-3 months of such treatment, until the level of 30-50 ng/ml is reached.
  • 10-20 ng/ml – in the case of deficiencies, one should always verify whether general recommendations were followed. If not, supplementation should be started according to recommendations, and then the level of 25-OH vitamin D should be tested again after 3 months. If supplementation was correct, the dose should be increased by 100%, and the level of 25-OH vitamin D should be tested again after 3 months.
  • 20-30 ng/ml – in deficiencies, one should always verify whether general recommendations were followed. If not, supplementations should be started according to recommendations, and then the level of 25-OH vitamin D should be tested again after 6 months. If supplementation was correct, the dose should be increased by 50%, and the level of 25-OH vitamin D should be tested again after 6 months.
  • 30-50 ng/ml – the optimum level of vitamin D3 in blood. With this result, it is recommended that general recommendations for the age group should be continued.
  • 50-75 ng/ml – if general recommendations were followed, it is recommended that the dose should be reduced by 50%, and the level of 25-OH vitamin D should be tested again after 3 months. If higher doses were taken, it is recommended that supplementation should be discontinued for 1 month and after that time, general recommendations for the age group should be followed.
  • 75-100 ng/ml – for such a high level of vitamin D3, one should check whether vitamin D3 was supplemented and in what dose. It is recommended that supplementation should be discontinued for 1-2 months. After that time, supplementation of minimum doses according to general recommendations can be resumed, until the level of 30-50 ng/ml is reached.
  • >100 ng/ml – if supplementation was used, it should be discontinued immediately, and the level of 25-OH vitamin D should be monitored every month. If it was not used, you should contact your doctor in order to eliminate other causes of such a high level.

IBS – Irritable Bowel Syndrome

What is IBS?

IBS – irritable bowel syndrome – is a chronic, idiopathic, functional condition of the digestive tract, manifesting itself by discomfort of the digestive tract, abdominal pain, disturbed rhythm of bowel movements, such as diarrhoea, constipation or diarrhoea with constipation. Approximately 25% of the population suffers from IBS, mainly women.

Diagnosing IBS

Disorders accompanying IBS can also be of organic origin (e.g. coeliac disease). Diagnosis of IBS must be preceded by a number of tests to exclude organic disorders. Please remember that IBS can be diagnosed only and exclusively by a physician.

Pathogenesis of IBS

Its aetiology is unknown. The following may contribute to IBS:

  • SIBO, i.e. small intestinal bacterial overgrowth,
  • irregularities in microbiome,
  • visceral sensitisation dysfunction and intestinal motor dysfunction,
  • psychological changes,
  • previous intestinal infections.

Multi-level treatment of IBS: diet, supplementation, pharmacotherapy, psychotherapy

Depending on an individual case, treatment of IBS often consists in multi-level therapy and collaboration of several specialists. The treatment is primarily based on introducing a special diet. A diet especially recommended in this condition is a temporary LOW FODMAP diet. It is also worth using supplementation, which is a very individual issue, however, probiotics, sodium butyrate and herbal preparations, e.g. Iberogast, are basic preparations that can be the most beneficial. Pharmacotherapy involving muscle relaxants or in certain cases even antidepressants is a frequent element in treating IBS. Psychological therapy is another level in treating disorders such as IBS.

Diet in IBS

A diet especially recommended in the irritable bowel syndrome is LOW FODMAP diet, i.e. diet with low quantities of easily fermenting polysaccharides, disaccharides, simple sugars and polyols. However, LOW FODMAP diet cannot be used all the time.

LOW FODMAP diet is divided into 3 stages.

Stage 1 – consisting in strict diet eliminating products rich in FODMAP:

  • lactose,
  • legume seeds,
  • rye and wheat,
  • fruit containing high quantities of fructose, such as apples, plums, apricots, mango, pear,
  • leeks, beetroot, onions, asparagus, Brussels sprouts, broccoli, cauliflower, green peas, garlic,
  • honey, agave syrup, glucose and fructose syrup, polyols (e.g. maltitol, mannitol, xylitol, sorbitol),
  • pistachios, cashew nuts,
  • mushrooms.

Stage 2 – consists in gradual introduction of individual products and monitoring the reaction of the organism.

Stage 3 – consists in creating an individual base of well-tolerated products and maximum personalisation of diet.

Numerous studies show that LOW FODMAP diet seems efficient in treating some patients with IBS. Introducing LOW FODMAP diet and then stepping back gradually from it and personalising the diet should always be supervised by a dietician.

Allergy or food intolerance?

In recent years, elimination diets have become very popular. When going on an appointment with a dietician, some people assume that certain products will be eliminated. Usually, it concerns eliminating gluten and/or dairy products. However, we must be aware of the fact that elimination diet is justified only in specific cases, and implementing it without consulting a specialist may bring more harm than good. Elimination diet is introduced following a thorough nutritional and medical examination and diagnostic tests based on referral from a specialist.


Food sensitivities can be divided into two types, depending on the involvement of the immunological mechanism. We distinguish between food allergies and non-immunological food sensitivities.

The general classification of food sensitivities is as follows:

  1. Food allergy – including the immune system
  • IgE-dependent allergy (atopic or non-atopic allergy),
  • IgE-independent allergy (allergy dependent on IgG, eosinophilia, T lymphocytes, etc.).
  1. Food sensitivity – not involving the immune system
  • enzyme intolerances, e.g. intolerance to lactose,
  • pharmacological intolerances,
  • idiopathic intolerances.


Let’s start with food allergies. In short, IgE allergies are immediate reactions, while IgE-independent (IgG-dependent) allergies are delayed reactions of the immune system. Both types of sensitivities are connected with an incorrect response of the immune system caused by an ingredient in our diet. The reaction consists in an increased number of IgE or IgG class antibodies in blood.

IgE-dependent allergies are easy to identify, because they are characterised by an immediate reaction (symptoms appear within several minutes to one hour after contact with the allergen). Symptoms usually involve the respiratory tract, skin or digestive tract.

In most cases, swelling, skin redness, urticaria, abdominal pain, runny nose or bronchospasm appears. An acute allergic IgE-dependent reaction may even lead to anaphylactic shock, which requires fast medical intervention.

It is also worth adding that not many people suffer from this condition – approx. 1-3% of adults and 4-5% of children. These allergies are diagnosed primarily during childhood.

Unfortunately, we cannot say the same about IgE-independent allergies. This issue still remains unclear and is a subject of numerous scientific studies, while it is estimated to affect more than 50% of the population.

Identification is problematic due to late symptoms, which can usually be observed 8-72 hours after contact with the allergen. To complicate things even further, intensification of symptoms is also connected with the quantity of a given ingredient of diet, and usually there are several ingredients and not one as in the case of IgE-dependent reaction.


In the case of food allergies, the problem is triggered by the immune system, which can be stimulated by genetic or environmental factors. Studies show that the majority of IgE allergies are acquired in the first two years of life. It is connected with immaturity of the immune system, which is very sensitive to external stimuli.

Among factors conductive to IgE-dependent food allergies are:

  • vitamin D3 deficiency,
  • incorrect diet during infancy,
  • environment pollution,
  • exposure to tobacco smoke.

Preventive factors:

  • breastfeeding,
  • including new ingredients in the child's diet in an appropriate way,
  • maintaining the right intestinal microflora.

In the case of IgG-dependent allergy, environmental factors are considered to have an increasingly larger effect. It seems that IgG-dependent allergies can result from the leaky gut syndrome, i.e. a condition in which the intestinal barrier becomes more permeable and non-digested food particles pass through the intestine, stimulating the immune system and leading to the development of an immunological complex and inflammation. However, these assumptions require further studies.


The immune system does not play any part in the mechanism of formation of these sensitivities. They usually concern food intolerance related to a deficiency of an enzyme. This can be, for example, intolerance to lactose, fructose, histamine, etc. Diagnosis is made based on breath and genetic tests. Treatment involves elimination diet and/or digestive enzymes supplementation.


Diagnostics of IgE-dependent allergies is simple and includes interview, immunological tests, such as the assessment of IgE antibodies in serum and skin tests.

IgE-dependent allergies are diagnosed on the basis of tests assessing specific IgG antibodies in relation to food ingredients.


A large variety of symptoms, which are often classified as conditions of unknown origin, make correct diagnostics difficult. Tests are usually recommended for people who are treated for diseases mentioned below and do not show any improvement. This primarily concerns the following conditions:

  • irritable bowel syndrome,
  • inflammatory bowel diseases,
  • autoimmunological diseases,
  • depression,
  • skin lesions (atopic dermatitis, acne, psoriasis),
  • chronic fatigue,
  • migraines,
  • recurrent infections,
  • infertility,
  • obesity and overweight.


From dietary point of view, the problem of obesity and overweight seems especially puzzling. Body weight reduction seems to be easy. With introducing a suitable caloric deficit and with a little bit of consistency the effect should be guaranteed. Unfortunately, it is not always this easy.  There are patients who despite reduced caloric intake still find it very difficult to lose weight. The situation starts to complicate even further if we are dealing with chronic inflammatory state connected with an increased level of inflammatory mediators (TNF-α, IL-1, IL-6 and CRP). It is worth adding that an excess of fat tissue alone will generate an inflammatory state. As a consequence of inflammation, other different conditions and diseases may appear, such as insulin resistance, diabetes, hypertension or atherosclerosis, which will additionally enhance the inflammation in the body, impeding all attempts of slimming. Body weight optimisation seems the first recommendation to improve the health situation. The problem is that in order to lose weight, inflammation needs to be dealt with first, as this state is certainly related to obesity, but may be intensified by IgG-dependant allergies. This is why IgG-dependent allergy tests are recommended to people who despite following dietary recommendations and physical activity still find it difficult to reduce body weight.

Studies show a positive effect of an elimination diet (based on IgG-dependent allergy diagnostic tests) on reducing body weight in patients having problems slimming down.

Recapitulating, the subject of food sensitivities is highly topical nowadays, and plenty of information is available from various sources. I recommend caution with self-diagnosing and eliminating entire groups of food products on one's own. An adequate elimination diet supported by suitable tests and/or an interview conducted by a specialist may bring considerable benefits, however, doing it on one’s own without consulting a specialist may lead to nutritional deficiencies and health deterioration.

Please remember that the key to health improvement is a holistic approach, diet rationalisation – without following temporary trends – and nurturing good habits.