What Is a Protein?

Answer:

A protein is a complex molecule that forms the basis of all life, and is composed of two or more amino acids. Protein is essential in the diet for growth, repair and replacement of tissue. Animal products (meat, fish, eggs, cheese) provide much protein in a form able to be used by the body. Vegetable proteins exist in peas, beans and other legumes, as well as in grains (and thus bread).

Protein from animal sources is called complete, because it contains all nine of the essential amino acids. Most vegetable protein is considered incomplete because it lacks one or more of the essential amino acids. This can be a concern for someone who doesn't eat meat or milk products. But people who eat a vegetarian diet can still get all their essential amino acids by eating a wide variety of protein-rich vegetable foods.

If more protein is eaten than the body needs it will provide extra energy, but if not used it will be converted to fat and stored.