All vital functions of the body are associated with nutrition. It is the source of development of tissues and cells, their constant renewal, a saturation of a person with energy. Improper nutrition – both excessive and insufficient – can cause significant harm to human health at any age. This is reflected in a decrease in the level of physical and mental development, rapid fatigability, inability to resist the effects of adverse environmental factors, decreased performance, and even premature aging and reduced life expectancy.