In discussing health and disease, it is important to define fiber as that part of fruits, grains, nuts, seeds, and vegetables that is not broken down by the enzymes in your digestive system, and so is not absorbed the way you absorb fats, proteins, and carbohydrate (starch and sugars). The fact that fiber is not digested by the enzymes in the stomach and small intestine previously led many to consider fiber a worthless component to be discarded (as in bran from wheat, or rice polishings from rice)