Composed of amino acids and nitrogen, protein is considered a macronutrient that, combined with carbohydrates and fat, plays a chief role in the building of muscles, the transportation of oxygen and the regulation of hormones.
As a macronutrient, protein is required in large amounts for achieving optimal health. Nitrogen in protein, for example, is a key factor in staving off infection as it promotes the growth of anti-bodies. A lack of protein results in loss of muscle mass, insulin imbalance and hormonal problems.
Foods that contain protein include eggs, meats, milk, cheese, soy products such as tofu and beans. How much protein-rich food an individual needs is contingent upon age, level of activity and gender. To calculate the approximate percent grams of protein required, an individual can multiply his or her weight by 0.6; although a very athletic person may require more protein in his or her diet than this approximation.