Fiber

Some foods contain fiber, a tough complex carbohydrate that is only partially digested by the body. The digestible part provides some calories; the indigestible part provides bulk to the feces. This bulk helps the intestine move feces along, thereby preventing constipation, and it reduces pressure in the intestine, helping prevent diverticular disease. Eating fiber also helps increase the elimination of cancer-causing substances produced by the bacteria in the large intestine and helps moderate the changes in sugar and cholesterol levels in the blood that occur after eating a meal. Authorities generally recommend that about 30 grams of fiber be consumed daily. In the United States, the average amount of fiber consumed daily is about 25 grams. An average serving of fruit, a vegetable, or cereal contains 2 to 4 grams of fiber.