Athletes and physically active people take nutritional supplements to improve their health, maintain their physical qualities and optimise the recovery process. At the same time, the specifics of their use and the mechanism of action in acute energy deficiency have not yet been definitively investigated, which makes the study of the effect of proteins and amino acids in the hypocaloric state of a person an urgent problem. The purpose of the study was to clarify the role and mechanism of the plastic and regulatory effect of proteins and amino acids with a branched chain on the body of athletes in hypocaloric conditions. The analysis of the literature was carried out using the methods of analysis, synthesis, systematisation and generalisation according to the method of using keywords in the electronic databases PubMed and SPORTDiscus. The peculiarities of the athlete’s hypoenergetic condition and dietary protein supplements to preserve the athlete’s muscle mass in the conditions of long-term physical tests have been clarified. It was found that with a limited level of calories and a low supply of fat, the need for protein increases almost twice. Taking protein within 2 hours after training or before going to bed stimulates a significant acceleration of muscle protein biosynthesis. The amino acid lysine in the composition of proteins activates the central regulator of anabolism of skeletal muscles – the intracellular multimolecular signalling target of rapamycin complex. Its regulatory signals are propagated by the cyclase system. As a result of the action of the appropriate protein kinase, reactions of phosphorylation of chromatin proteins, participants in processing, splicing, etc. occur. It is assumed that in this way lysine stimulates the rate of synthesis of various regulators and factors of anabolism, remodelling and growth. A hypothetical mechanism of the influence of leucine on the anabolic processes of muscle tissue is proposed in a graphic version. The study will be useful for specialists in biochemistry, sports nutrition, sports and wellness industries
KUIBIDA et al. (Wed,) studied this question.