In this first article you can find the indications for an athlete’s correct diet, in the next article I’m going to explain more into detail the timing of nutrients with reference to physical activity: before, during and after training.
I start by saying that it’s a very broad subject and the indications vary according to the type of sport practiced, the individual and the objective that the subject wants to achieve.
During the effort the body needs energy, the catabolic hormones activate themselves increasing the mechanisms by which the body breaks down macromolecules to provide energy such as glycolysis; the cells during the activity become more receptive and the flow of energy is conveyed to the muscles.
Once we have finished training the muscle cells have increased their receptors on the membrane, this leads to an improvement in cell uptake and they are able to capture sugars and amino acids much more easily.
Nutrition for a sportsperson is essential for:
- Improve efficiency and training performance
- speed up recovery in order to be ready for the next session
- prevent and/or alleviate any trauma and damage
- satisfy energy needs
- achieve and maintain the ideal physique in terms of weight, fat mass and lean mass
- maintain optimal health and reduce the risk of disease
Let's see a quick overview of the three macronutrients (carbohydrates, proteins, lipids) with their main characteristics and the roles they play in the performance of physical activity.
1. Carbohydrates: They ARE NOT ESSENTIAL but ARE NECESSARY
There are two types: simple (monosaccharides, disaccharides, oligosaccharides) and complex (polysaccharides). The former, commonly called "simple sugars", are found in fruit, sweets, honey, chocolate and natural sweeteners and are composed of 1 to 9 molecules of monosaccharides. Some examples are: glucose, fructose, lactose and sucrose.
Complex carbohydrates, on the other hand, consist of more than 10 molecules of monosaccharides and are found in plants in the form of starch and fibre and in mammals as muscle and liver glycogen.
A low carbohydrate diet causes a rapid reduction in glycogen reserves at the muscular and hepatic levels, influencing the athlete's ability to perform prolonged or high intensity physical activity. Therefore, the diet of the athlete should contain 50-60 % of the kilocalories in the form of: starches derived from cereals mostly whole (rich in fiber) and unrefined, vegetables and fruit. These percentages may vary according to the objective to be achieved, the type of training and the quantity of training.
2. Lipids: they provide the greatest energy reserve of our organism stored in the subcutaneous and visceral adipose tissue, they are an energetic substrate of the muscle during rest and aerobic activity, they constitute the structures of the nervous tissue, they give taste to the foods, they have a protective action against the vital organs, they provide thermal insulation from the cold and they act as carriers for the fat-soluble vitamins (A, D, E, K).
The lipids present in food are mainly triglycerides, i.e. molecules composed of three fatty acids and one molecule of glycerol. They are the most abundant fats in our body representing the main form of fat deposit in fat cells.
Fatty acids are divided into saturated, monounsaturated and polyunsaturated:
- The former are commonly found in foods of animal origin such as meat (especially in red meat), egg yolk, dairy products, coconut or palm oil. High consumption can lead to an increase in plasma cholesterol, increasing the risk of cardiovascular disease.
- Monounsaturated fatty acids are oleic acid, which is the main constituent of olive oil.
- Polyunsaturated fatty acids are found in vegetable sources such as dried fruit, algae, linseed, chia seeds and in some vegetable oils (e.g. sunflower oil) and in animal sources such as fish (eel, sardines and tuna). These, unlike the saturated ones, are to be preferred because they would seem to help in the fight against cardiovascular diseases.
The lipid content of the sportsman's diet varies according to the type of activity carried out, the frequency and the volume BUT the indicative range is between 20% and 35% of the total energy of the diet.
3. Proteins: these are macromolecules that perform numerous functions, including structural, mechanical, enzymatic, in the immune response and in the cell division cycle.
They are made up of "bricks" called amino acids. Of these, 8 are essential (isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine) because our body is not able to synthesize them, and it is therefore necessary to introduce them through the diet.
Proteins containing all essential amino acids are defined as complete or of high biological value (meat, fish, eggs, milk and derivatives), while the others are called incomplete or of low biological value.
In sportsmen and women, the quantity of proteins required increases, so it is important to take them through food and/or supplementation. The greatest demand is given by the need to support the synthesis of cellular material during anabolic processes (construction) after exercise and avoid protein catabolism (destruction) due to the emptying of glycogen reserves, which in sedentary individuals happens to a lesser extent. In addition, the increased needs are due to the increase in muscle mass.
It is essential to vary the foods consumed during the week in such a way as to provide our body with all the different types of nutrients and substances that it needs to perform its functions. In addition to carbohydrates, proteins and lipids (which are almost always taken regularly) there are micronutrients such as minerals and vitamins that are essential components that the body can not produce so it is necessary to introduce them by choosing different varieties of fruits, vegetables, fish, meat, legumes etc.. In addition to a better physical shape, changing the diet means preventing certain types of disease.
By Federica Mascaretti