Protein is one of the three major, or macro, nutrients. Unlike carbohydrates and fats (the other two types of macronutrents), proteins are comprised of nitrogen-containing groups called amino acids. There are about 20 different types of amino acids commonly found in foods. All of them are important for building and maintaining muscle, but 8 are vital. These are what’s known as the Essential Amino Acids (EAAs). Contrary to what most athletes believe, there is no actual requirement for protein; the body simply has a requirement for the eight essentials.