Proteins are another very important macro-ingredient necessary for proper functioning of the body. Synthesized by all tissues and organs, they are built of endo- and exo-genous amino acids. Endogenous amino-acids are produced within the human body, while exogenous amino acids (EAA)need to be supplemented externally. EAA contain such acids as BCAA or arginine, with huge influence on building muscle mass, increasing energy levels and regeneration. Tests have proved that an average person with medium to low levels of physical work requires only 1 gram of protein per one kilogram of body weight daily. With large amounts of physical strain, such as in heavy weights training, this quantity increases dramatically. A minimum quantity required to successfully build muscle mass has yet not been established. An average has been set of 1.6 – 1.8 g of protein per 1 kg body mass, when building body mass the natural way. Examples of natural protein sources: chicken eggs dairy lean meat fish The last