The book systematizes the main classes of dietary supplements and specialized foods designed to improve the physical and functional fitness of professional athletes, amateurs and everyone who leads an active lifestyle; mechanisms of influence of biologically active substances included in composition of modern food additives are described, rationality of their use in representatives of different sports is analyzed. The monograph contains information on nutritional and metabolic support in syndromes of microdamage of muscles and delayed muscle soreness in athletes, on food supplements for body weight control and blood lipid profile, and also highlights the possibilities of using ergogenic agents of a nutritional nature in vegetarians and vegans during physical exertion.