An adequate diet must cover the energy needs generated by training and competition as well as optimize recovery. Food is therefore to humans what fuel is to an engine. Our energy needs vary according to the type, duration and intensity of the activity practiced, we must adapt our food intake to our needs. The main nutrients are 3 in number and are called carbohydrates, proteins and lipids (fats). The athlete’s food pyramid tells us in what quantity we should consume them as well as their main resources.
Carbohydrates (= carbohydrates)
Carbohydrates, also called carbohydrates or more simply sugars, are the main fuel used during exercise. They are stored as glycogen in the muscles and the liver. These stocks contain enough reserves to allow a high intensity effort over a period of 60 to 90 minutes (up to a maximum of 120 minutes). The famous “marathon wall” corresponds to a total depletion of glycogen reserves.
This is because carbs aid in fat metabolism and if you are carb deficient, like during the marathon wall, nothing works. The fat metabolism cannot therefore take over until a little carbohydrate is digested and ready, in the form of glucose, in order to restart the 2 metabolisms. In order to avoid the depletion of glycogen stores and therefore this physiological failure, it is crucial to eat carbohydrates regularly (in the form of sugary drinks or snacks) during prolonged efforts. Carbohydrates are considered the most efficient source of energy, since for the same amount of energy produced, the amount of oxygen needed is less than that needed to produce energy from lipids or proteins. .
How to indicate and measure energy?
The official unit of measurement for energy is the joule. However, an old unit is still used today, it is the calorie.
1 calorie = 4.184 joules*
*In everyday language, we speak of calories and joules, however it would be more correct to speak of kilocalories (kcal) and kilojoules (kJ). One kilocalorie equals 1000 calories.
Proteins are nutrients, the main function of which is the synthesis and repair of muscles and most of the tissues of the human body. Training in itself leads to the destruction of certain muscle fibers, the repair of which requires the supply of protein. In addition, proteins are also used to produce certain hormones or other enzymes. Normally, proteins are not used for energy production. However, during a prolonged effort, and if our body is in energy debt, we are then able to “digest” our own muscles to produce energy. This is obviously counterproductive both in competition and in training. A balanced diet covers the protein needs of the vast majority of athletes. Meat, poultry, fish, eggs, dairy products and certain foods such as tofu and oilseeds are the main sources of protein. Proteins themselves are made up of subunits called amino acids. The majority of these amino acids can be synthesized by our body from other substances, however some amino acids, called essential amino acids, cannot be produced by our body and must be provided by food. In general, proteins of animal origin, comprising a wide variety of amino acids, cover our intake of essential amino acids. On the other hand, proteins of plant origin have a much more limited amino acid variety. Thus, a vegetarian wishing to cover his essential amino acid needs will have to be careful to combine different sources of vegetable proteins in order to ensure his essential amino acid needs. The recommended daily protein intake is 1g/kg of body weight for amateur athletes. Athletes participating in team sports, strength sports (maintenance period) and endurance sports (maintenance period) have a slightly increased protein requirement (1.2-1.4 g /kg). For these two categories, a varied diet can cover these needs. During growth, adolescence (2g/kg) but also during periods of intensive training (strength or endurance) (1.7 g/kg) the recommended intakes are higher.
In these cases, a diet comprising four daily protein servings (alternating meat, fish, eggs, cheese and vegetable proteins) is necessary. Additional protein intake in the form of a dietary supplement is also recommended.
Lipids, also called fats, provide the fuel for long-lasting exertion and are essential for the transport and absorption of fat-soluble vitamins. They provide twice as much energy as carbohydrates or protein (9 calories per gram of fat versus 4 calories per gram of carbohydrate or protein) and are therefore a virtually unlimited source of energy for athletes. Indeed, our body transforms and stores all excess calories from any food source (fat, carbohydrate, protein) into body fat. We therefore have enormous amounts of lipids, which are useful to us for endurance efforts. Thus, it is commonly accepted that there is enough fat stored in muscle fibers and in fat deposits to perform 100 hours of physical activity. Lipids are the main fuel during aerobic physical activity. Their use makes it possible to delay the moment when glycogen will be metabolized. Using fats for as long as possible during a given effort thus allows you to save glycogen reserves and to continue the effort, even at high intensity. In terms of dietary recommendations, it is therefore advisable to include a moderate amount of healthy fats in your daily diet, such as nuts, vegetable oils (eg olive or rapeseed oil), or even a portion of butter (approx. 10g). For every hour of physical activity, half a serving of fat should be added. This may come as a surprise given that fats have a bad reputation in the general population. However, recent studies emphasize the importance of dietary fat intake. It should be noted, however, that there are several types of fats and that it is still relevant to avoid the fats found in cookies, crisps, fries and all foods “at the Spanish”, as well as fats of animal origin (e.g. salamis, sausages). These foods can be eaten and savored,