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Synonyms of the term “proper nutrition” are “rational”, “balanced”, “adequate” and some others. All these names are equivalent in meaning2. Nutrition is considered rational if it satisfies the body’s needs for all substances and energy3.

Rational nutrition for each person is not a certain constant value. On the contrary, it is a variable value, it changes with age, depends on gender, ethnicity, level of physical and psycho-emotional activity, health status, external factors2