Fat, like protein and carbohydrates, is a principal and essential component of the diet. Fats and oils are predominately triesters of fatty acids and glycerol, commonly called triglycerides. When appearing as solids, they are called fats and when liquid they are called oils. Fat is the body's most concentrated source of energy.
Some dietary fat is vital to enable the body to function properly.
Fat provides essential fatty acids necessary to the structure of cell membranes and prostaglandins. Liquid vegetable oils are the major source of vitamin E in the diet. Fat is vital to human growth and development. American men and women currently consume 34 percent of their total energy from fat. Health authorities recommend a fat intake of 30 percent or less of total energy for people.