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 małysz 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 - 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?

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 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 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).


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).


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.


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.


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.


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.


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.



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 a sports 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.



Let's answer the question: to eat or not to eat before the workout? 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.






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.


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.


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.


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.


Diet and physical activity are two elements of a puzzle complementing each other in the achievement of slim figure and sports goals. There is no doubt that we have to eat (!) As a consequence of not eating, the organism’s quick reaction will be the loss of concentration and muscular strength, getting tired faster, slower regeneration and lack of effects of the workout. If you have experienced some of these symptoms or want to avoid this state, keep on reading.

What does pre- and post-workout diet depend on?

One unequivocal answer to the majority of questions on nutrition in sports does not exist, because of many related factors, such as:

  • current goal,
  • sports discipline,
  • workout intensity and frequency,
  • body composition,
  • health condition,
  • individual tolerances.

Adequately selected pre- and post-workout meals contribute greatly to faster regeneration and better workout effects, thus, better results and goal achievement.
Do not forget that exact recommendations depend on your current goal, sports discipline, frequency of workouts, body composition, and individual tolerances. Contact a dietician in order to select an individual plan, and you should use this article only as general recommendations on a pre- and post-workout diet.

Pre-workout diet

A pre-workout meal should meet the following criteria:

  • provide energy for the work of muscles,
  • replenish liver glycogen (in the case of a morning workout session),
  • replenish muscle glycogen,
  • protect against hunger during workout,
  • for strength and velocity sports – protect the muscle mass against catabolism.

When composing a pre-workout meal, a lot depends on the athlete's tolerance, i.e. how much time before workout he/she can eat the meal not to feel hungry during workout on one hand, and for the meal to get digested on the other hand.
It is recommended to eat a meal based on low-GI products in the proportion of 1-4 g per 1 kg of body weight 1 to 4 hours before workout. Exact values depend on the athlete’s tolerances and well-being.

Carbohydrates before workout:

Carbohydrates should be the basis of a pre-workout meal in most sports disciplines. Sugars before workout will provide fuel for muscles. It is worth choosing products characterised by low GI and low in fibre. For example, kasha commonly considered to be wholesome will not be a good solution here. Millet groats with fruit will be a better choice.

Protein before workout:

It depends, mainly on the time remaining until workout, individual tolerances and the nature of the workout. For a strongman and a person developing the body mass consuming protein before workout is obligatory, but for a long-distance runner not necessarily. It is worth remembering that protein is digested slower than carbohydrates, and fast absorbing protein, e.g. whey protein, preferably in the form of a isolate, or the fastest absorbing hydrolysate, should be chosen at that time.

Fats before workout:

Fats are food ingredients which we usually avoid in pre- and post-workout diet. It mainly concerns avoiding fried meals and products rich in fats. It is because they slow down digestion and may slightly impede blood flow in blood vessels, which is definitely undesirable during workout. On the other hand, not all fats are the same. MCT, i.e. medium-chain triglycerides, are an exception here, because they get digested rapidly. At the same time, they are a stable energy source, thus, protecting muscle glycogen, and improve resistance, which is especially favourable in sports such as running or cycling.

Post-workout diet

The main goals of post-workout diet:

  • muscle glycogen replenishment,
  • provision of substrates for repletion of damaged muscle fibres,
  • water resources replenishment,
  • acid-base balance restoration.

What, how much and when we should eat after workout depends on many factors: mainly on our goal, level of physical fitness, body composition, degree of muscle damage and frequency of workouts. Regeneration is the fastest during two hours after workout. Our metabolic rate is the fastest as well. Post-workout eating depends to a large degree on the time left until the next workout. The shorter the time until the next workout (4-8 h), the more aggressive strategies need to be adopted, and the greatest attention must be paid to food and regeneration. If the break between workouts is more than 12 h, then we can follow standard recommendations. It is also worth mentioning that our regeneration rate is directly proportional to the level of physical fitness, and this is why professional sportsmen can train with more frequency. It is due to a faster glycogen resynthesis rate, which results from adaptation to physical effort.

Carbohydrates after workout:

Carbohydrates are a nutrient which is especially recommended in a post-workout meal, because they play the main role in muscle glycogen replenishment. Post-workout meal is the best moment during the entire day to consume carbohydrates because of a specific metabolic window and increased sensitivity to insulin, which considerably accelerates metabolism. According to general guidelines, 1 g/kg of body weight of carbohydrates should be consumed within 2 hours after workout (this applies to people with an appropriate body weight). Depending on the workout intensity and nature as well as the athlete’s tolerance, different consistency of meals is recommended, however, directly after workout, meals in liquid or semi-liquid forms are recommended, followed by a solid meal.

Protein after workout:

Protein after workout is necessary as a substrate to replenish damaged muscle fibres. Studies prove that protein combined with carbohydrates significantly improve muscle glycogen replenishment. Protein in a post-workout meal is indispensable if our goal is to develop our body mass and strength and to regenerate our body. In such a case, our meal should contain 20-40 g of protein. It is also worth including a source of lightweight protein with a high leucine content. A rich source of whey protein is curd cheese or ricotta, while a convenient way of consuming it is a protein supplement in the form of whey protein hydrolysate or isolate, i.e. the popular WPH or WPI.

Fats after workout:

Fats should be avoided, especially in a meal directly after an intensive workout.

Glycemic index of products:

Products with high GI are usually recommended in a post-workout meal due to the fact that they accelerate glycogen replenishment. On the other hand, studies show that a low-GI meal consumed after workout increases resistance and speeds up fat tissue burning. This is why a lot depends on the athlete’s individual goal and the current training period.