Diet and workouts – what should I eat when I am physically active?

A proper diet has an influence on the effects of a workout. What should I eat to build muscles and, at the same time, keep my body fat percentage low? What nutrients should my diet be composed of? Let us give you a clue.
Dieta a trening
Dieta a trening

A properly designed diet is one of the important elements of a person who does sport. What, how and when you eat is also important. Although it is recommended to tailor a diet (based on type of physical activity, sex or culinary preferences), there are some general rules that should guide you when you develop your meal plan. What and why should be included into a sportsman’s diet?

Diet and a workout – carbohydrates 

Workout makes your body need more “fuel” in the form of carbohydrates. This is the main source of energy for a physically active person. Also fats and protein fulfil your need for energy, but to a lesser extent. The more intense the workout, the more carbohydrates you need. And vice versa – the less intense the workout, the lower the ratio of carbohydrates in your diet and the higher the ratio of fats should be.

Carbohydrates are essential primarily for professional sportsmen but also for people who do very intense workouts. That is because the body uses carbohydrates to produce glycogen which is necessary for the muscle during intensive work and glucose, that is the source of energy. It is estimated that each gram of carbohydrates provides about 4 kcal of energy necessary to function. It is assumed that carbohydrates should provide 40 to 70 percent of energy in the diet. However, you should be careful with the excessive consumption. Excess carbohydrates intake may easily lead to increase in bodyweight (which suits some people).

How many carbohydrates do you need? It all depends on the intensity of the workout.

  • Low need – skill training or very light workout: 3 – 5 g of carbohydrates per one kilogram of body weight;
  • Moderate need – 1 hour of intensive workout a day: 5 – 7 g/kg b.w.;
  • High need – 1 to 3 hours of intensive workout a day: 6 – 10 g/kg b.w.;
  • Very high need – 4 to 5 hours of intensive workout a day: 8 – 12 g/kg b.w.

Carbohydrates delivered with food are different in two ways. First of all, they can be divided into simple carbohydrates (in other words simple sugars or monosaccharides) that are easily absorbed by the body as they do not break down to smaller particles and complex carbohydrates that require time to be absorbed, as they have to be broken down to simple sugars. Yet another division distinguishes low-, medium- and high-glycaemic index (GI) sources of carbohydrates in a diet. GI gives us information on the extent to which a given product increases blood glucose levels compared to pure glucose. When a product’s GI value is 70 to 100, it is a high GI product. When a product’s GI is below 55, it is a low GI product.

Proper sources of carbohydrates in the diet of a person who does workouts includes whole cereal grains and their products and also fruit and starchy vegetables.

It is also worth to mention about fats that should provide about 20 to 30 percent of energy (at least 15 percent) to people who do workouts. It should be mentioned, however, that they should be mainly fats of vegetable origin, like olive oil, cold-pressed oils or nuts. A low-fat diet slows down metabolism and has a negative influence on muscle development.

Diet and a workout – protein

Protein is a basic component of each cell in the body and – like carbohydrates and fats – a source of energy necessary for metabolic processes. Therefore, it is important in a diet of a sportsman, both in the process of body mass building and regeneration of muscles after a workout.

Note – contrary to what one might expect, the assumption: the more protein I eat, the more muscles I have, is erroneous. It is a fairly misleading myth for people doing workouts. As dr. Damian Parol writes (link:, excessive consumption of proteins may impede the absorption of other nutrients and energy supply. Numerous studies and standards indicate that insufficient supply of fats and carbohydrates results in the use of protein, which compromises the protein metabolism in the body (as a result high-protein diets may lead to the so-called ketosis and subsequently to renal damage).

How much protein should I eat, to provide its optimal amounts to my body? According to the “Nutrition standards for the population of Poland” developed by FNI (link:, a person whose level of physical activity is low should provide about 0.9 g of protein per one kilogram of body weight a day. What amount of protein should be eaten by individuals who do workouts?

  • 1.2 to 1.4 g/kg b.w. – endurance workout, like running, cycling, swimming
  • 1.2 to 1.7 g/kg b.w. – strength workout and strength and endurance workout, like weightlifting and powerlifting, martial arts
  • 1.6 to 2.2 g/kg – workout focused at muscle mass building, like bodybuilding

What is important, the protein sources should be broken down evenly into all 4 to 5 meals and snacks that are consumed daily. This will ensure its optimal use by the body. The amount of protein in each meal should amount to about 20 to 40 g.

What protein products should I select? You should primarily select the products that are the source of complete proteins. As stated in “Nutrition standards for the population of Poland” developed by the Food and Nutrition Institute, complete proteins: “include all the necessary amino acids in the proportions that allow for their maximum use in the synthesis of systemic proteins and for growth needs of young organisms, but also to ensure nitrogen balance in the body”. Therefore, the following products should be the source of proteins in a diet of a sportsman: lean meat (turkey, chicken), fish, low-fat, unsweetened dairy products (not necessarily zero-fat products, i.e. “light” products), and also eggs. The diet should also include plant products that are a good source of protein, especially leguminous vegetables such as soy and its products.

Turkey in a diet of a sportsman – why should I include it into my diet

According to the recommendations of the World Health Organization (WHO) and of the Polish Food and Nutrition Institute, a properly balanced diet should include such sources of protein as meat, for example. We should primarily choose white meat – turkey or chicken meat. It should be noted that in burrowing poultry (like turkeys and hens) we observe higher protein content than in waterfowl poultry (ducks and geese).

Particularly the pre- or post-workout meals should include turkey meat, which is characterised by high protein content (according to various studies, turkey breast provides about 19-20 g of protein per each 100 g) and low content of fats (including saturated fats) and sodium. When compared to other types of meat, it also provides less calories – in the case of turkey breast it is about 90 kcal per 100 g of meat.). 

Other nutrients present in turkey meat are equally important. First of all, it is thought to be a good source of B vitamins, particularly vitamin B3 (niacin), B6 and B12. They take part on numerous processes happening in our bodies: they support normal energy metabolism and help to maintain normal psychological functions. Turkey meat is also a source of such minerals, as zinc, potassium and phosphorus.   Potassium supports normal functioning of the nervous system. Zinc helps to maintain normal fatty acids metabolism. Phosphorus helps to maintain healthy bones and teeth.

Diet and a workout. Pre-workout meal – what should I focus on?

Pre-workout meal is normally eaten about 2 to 3 hours before physical exercise. It should be a normal, well-balanced, not too big meal. At best, it should contain light products, that do not cause bloating but also as nutritious as possible. You should avoid large amounts of fibre in the form of excess of vegetables or too large amounts of fats (e.g. oils, nuts or seeds). You should select light sources of carbohydrates, and a portion of protein – especially when you do weightlifting workouts. The meals should also provide salt, that is perspired in sweat during a workout.

You should also remember about proper hydration. We lose water during physical exercise, therefore we should make sure the amount we perspire is not excessive for our bodies. Steamed turkey breast with white rice and a portion of vegetables or oatmeal with milk or 0% yogurt and dried fruits are good examples of nutritious pre-workout meals.

Diet and a workout. Post-workout meal – what should it include?

After a workout, especially an intensive one, you should eat a protein and carbohydrate meal that will allow for muscle regeneration. It will provide building components in the form of proteins, and carbohydrates to rebuild glycogen reserves. It is not true that this meal should include simple carbohydrates with high GI and that after the workout you should definitely drink a cocktail, for example. After the exercises you may eat a meal you would eat at this time of the day, as well, e.g. dinner, like turkey or lean fish with vegetables and groats. It is also untrue, that after a workout the excess calories coming from the meal will be used anyway, so be careful not to overeat.

How soon after the workout should I eat something? You should wait about 45 to 60 minutes, as during the exercises – especially intense exercises – the blood flows from the gastrointestinal tract to muscles, to nourish them. Therefore, right after the exercise your body is not ready to start digesting. A meal will nourish your body equally well, if it is eaten an hour after the workout, or even later, e.g. two hours after the workout. In the 90’s there was a theory, that proteins and carbohydrates should be provided right after the exercise. It is not necessary, if you are not planning another physical exercise in the next few hours. In 2013, a metaanalysis of 23 studies was published. Its authors (Schoenfeld, Aragon and Krieger) observed that there is no evidence that eating shortly after a workout is important for regeneration of tissues, muscle mass building or growth of strength. According to the latest knowledge, delivery of protein to the body at regular time intervals throughout the whole day (every 3-4 hours) is more important to build the muscle mass. As a result, the post-workout meal will probably be eaten about 2 hours after we have finished exercising. Preferably it should be an apple that is easily absorbed, protein supplement, yogurt or lean meat (like turkey), for example. We should avoid products that extent digestion, like to large amounts of fibre. The portion of protein may be served with rice cakes or rice and some fruit (e.g. in the form of jam) or vegetables (e.g. salad or sauce).

However, we should not wait with water – we should drink it particularly when the meal was intense and we perspired a lot. You may drink right after the workout, and it should be delivered in the post-workout meal, in the form of vegetable soup with meat and rice.