For the last couple of decades it has been especially important to take healthy energetic food. Quality, quantity and the form of food which one takes should be suited to metabolic requirements of the organism which is exposed to heavy physical and psychological strain involved in the present day fast way of life.
Specific role and fate of all nutrients in metabolic processes are studied by scientific methods (researches in physiology, biochemistry, sports medicine), resulting in adequate ratio of food intake (quantification) and possible supplementation by certain nutrients.
The basic principles and rules that refer to diet of healthy people can simultaneously be applied to analyze and plan diet of sportspeople.
With sedentary people daily requirement for energy is between 2000-2800 kcal, whereas with sportspeople these requirements are much bigger and reach up to 9000 kcal per day and with professional cyclists even 12000 kcal per day.
In the outer world there are various kinds of energy, but the energy of food composed from carbohydrates, proteins and fat must be converted into usable forms which are called adenosine-triphosphate (ATP).
Energy of muscle activity is based on degradation and restoration of ATP and there are three metabolic processes during which ATP is created: 1.phosphagenic 2.glycolitic (lacticide) 3.aerobic (oxidative)
1 kcal = 4 kj
1 l O2 = 5 kcal
1 g carbohydrates = 4 kcal
1 g protein = 4 kcal
1 g fat = 9 kcal
1 g alcohol = 7 kcal