Fiber is one kind of carbohydrate. It is sometimes called roughage or bulk. Fiber is the part of plant foods that our bodies do not break down during digestion. Because fiber isn't digested, it doesn't give us calories. Foods that contain a lot of fiber may also contain other types of carbohydrates like starch or sugar. While we do not get calories from the fiber in these foods, we do get calories from the sugars and starches they contain.

Fiber is important for keeping the digestive tract working smoothly. Since we do not digest it, the fiber in food passes into the intestine and absorbs water. The undigested fiber creates "bulk" so the muscles in the intestine can push waste out of the body. Eating enough fiber helps prevent constipation. It may also reduce the risk of getting colon cancer. Some fibers can help lower blood cholesterol.

Dried peas and beans like lentils, black-eyed peas, chickpeas and kidney beans are the best sources of fiber. The skins and seeds in fresh fruits and vegetables are good sources, too. Whole-grain cereals and breads like oatmeal, brown rice, grits and whole-wheat bread are all naturally high in fiber.

Often the fiber in plant foods (like skins, bran or seeds) is removed when the food is cooked by us or processed by the manufacturer. We get more fiber when we eat whole fruits and vegetables with the peels and seeds than we do when we eat foods like applesauce or instant mashed potatoes. When we shop we can look on food labels to find products that say "100%" whole grain. We can also compare the Nutrition Facts to find foods with more fiber.

To find out more about other types of carbohydrates, read the files "Carbohydrates" and/or "Sugars".

To find out how much fiber you need every day, go to "Ask the Nutritionist."

To test what you know, take the Quiz on Fiber.
