The BCAA are made up of three essential amino, leucine, isoleucine, and valine. They are essential because the body is unable to make them out of other amino acids, meaning they must be ingested through food or supplements. The BCAAs make up 40 percent of the daily requirement of all nine essential amino acids, indicating their importance. The BCAAs are found in foods containing protein, with the highest concentrations in chicken, beef, salmon, eggs, and whey protein. The more BCAAs that are present in the muscles, the more they will be used for energy, slowing the breakdown of muscles cells and preventing muscle loss.