vegetarianism in sport

Vegetarianism in sport

TEXT/ KLAUDIA BUCZEK, KAROLINA FERDYN, MICHAŁ MIŚTA

Contents

  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.

Digestibility
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.

protein

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.

seitan

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].

omega-3

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.

creatine

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.

Conclusion

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.

Text / KLAUDIA BUCZEK, KAROLINA FERDYN, MICHAŁ MIŚTA

Contents

  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.

Introduction

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.

Regularity
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].

Conclusion

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.

Bibligraphy

  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?

Text / KLAUDIA BUCZEK, MICHAŁ MIŚTA

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.

Contents

  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.

Fats

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.