Protein can be converted into energy, but it's primary job in the body is to provide the building blocks needed for growth, repair, and the maintenance of body tissues. Protein is found in practically every food. Some of the richest sources of protein are meat, eggs, dairy products, beans and nuts.

    During digestion, protein is broken down into the building blocks used to repair the body known as Amino Acids. There are 20 Amino Acids, 9 of which are essential (must be gotten from diet, they are required by the body but cannot be manufactured). While most foods contain protein, only animal protein contains all 9 essential amino acids in proportion and is therefore considered “complete protein”. Vegetable protein is incomplete because each source is low in one or more essential amino acids. Proteins from different plants may be combined to provide complete protein for the body. This is also the body's last line of energy. Once all fat reserves have have been utilized, the body will begin to break down muscle tissues for fuel. However a surplus of amino acids in the bloodstream will also be converted to fat.