This scientific method is based on consuming foods containing high biological value index proteins and low fat and carbohydrate index proteins. Thereby, certain metabolic changes in the body take place and the body supplies itself with the required energy from its own fat reserves. Thanks to the low carbohydrate intake, hypoinsulinaemia (low level of insulin in the bloodstream) occurs, which also causes lipolysis (decomposition of fat). Fatty acids oxidize into ketone bodies, which become source of energy having anorexic effect - absence of hunger and spiritual effect - good mood with a lot of energy. As a result of the foregoing metabolic changes, the protein diet is characterized by absence of hunger, good mood, rapid loss of body fat and retention of muscles.