Energy foods are those that can be rapidly oxidized by the body to release energy and its by-product, heat. Carbohydrates, fats, and proteins provide energy for the human body, but carbohydrates are the primary source. They are the least expensive and most abundant of the energy nutrients. Foods rich in carbohydrates grow easily in most climates. They keep well and are generally easy to digest.
Carbohydrates provide the major source of energy for people all over the world (Figure 4-1). They provide approximately half the calories for people liv-ing in the United States. In some areas of the world, where fats and proteins are scarce and expensive, carbohydrates provide as much as 80 to 100% of calo-ries. Carbohydrates are named for the chemical elements they are composed of—carbon (C), hydrogen (H), and oxygen (O).