Fat (definition): one of the three main classes of foods and a source of energy in the body.  Fats help the body use some vitamins and keep the skin healthy.  They also serve as energy stores for the body.  In food, there are two types of fats, saturated and unsaturated (NASM, 2008).

Fat (function): serve as an energy source and facilitate the use of vitamins by the body. They also provide satiety and warmth for the body (NASM, 2008).