Biochemical Foundations of Human Vital Activity - Volkov, N.I., Nesen, E.N. 2000

Biochemistry of Sports
Biochemical Foundations of Rational Nutrition for Athletes
Balance of Nutrients in an Athlete's Diet

Balanced intake of CARBOHYDRATES, fats, and Proteins. It is currently established that optimal satisfaction of human energy and plastic requirements is achieved through a balanced Dietary intake of carbohydrates, fats, and proteins in a ratio of 4:1.2:1. In this case, carbohydrates should account for 50–55 %, fats for 30–35 %, and proteins for 10–15 % of the total caloric value of the diet (Fig. 211, a).

For athletes, The ratio of carbohydrates, fats, and proteins may vary depending on the Specifics of the sport, as well as the volume and intensity of the work performed, accounting for 40–70 % of total energy intake from carbohydrates, 20–42 % from fats, and 10–22 % from proteins. The general rule for balancing an athlete's diet is that in endurance sports, The amount of carbohydrates increases to 55–65–70 % of total daily caloric intake by reducing fats to 20–30 % and proteins to 10–12 % (Fig. 211, b).

Balance of individual food products. Food products should be selected to match the scheme shown in Fig. 211, c. The proportion of various foods in the daily diet should be as follows: 1/3 of the daily diet should consist of complex carbohydrate sources, 1/3 of protein-rich foods, 1/3 of fruits and vegetables, and a minor portion of fats and simple carbohydrates (sugar).

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Fig. 211 Balance of major nutrients for a non-athletic adult (a) and an athlete (b), as well as daily dietary food components (c)

TABLE 43. pH reaction of food ash

Carbohydrates in the diet should largely (up to 65 %) consist of complex carbohydrates (Polysaccharides). The daily requirement for dietary fats should be met by 70 % animal fats and 30 % plant-based fats containing mono- and polyunsaturated Fatty acids. Animal products serve as sources of complete proteins.

Acidity and alkalinity of food products. Food products contain certain amounts of acids and alkalis, and therefore can influence the acid-base balance in the body by shifting it toward the acidic or alkaline side. The body's buffer systems counteract this process; however, their capacity is limited, and muscular activity leads to the accumulation of acidic metabolic products. Consequently, it is necessary to limit the intake of acidic foods after intense physical exertion to prevent an increase in the acidification of the athlete's internal environment.

Acidifying foods include bread and other grain products, as well as meat, fish, and eggs, the acidity of which is determined by the ash reaction of the food products (Table 43). Vitamins influence the accumulation of acidic and alkaline components in Tissues. For instance, a deficiency of vitamin B₁ in the body limits The oxidation of pyruvic and other organic acids, which promotes the acidification of the internal environment and predisposes the body to diseases.