Fiber will not cure or prevent all diseases, but it should be a part of a healthy diet. Most fibers are carbohydrates. Our bodies cannot digest them. Thus the fiber portion of the food does not contribute calories to the diet. There are different types of fiber in your diet - cellulose, hemicellulose, pectin, gums and lignin.
Different plants have different types of fiber.
The fiber in oats for example, is different from the fiber in celery. The amount of fiber varies from one kind of plant to another and may vary within a species or variety. By eating a variety of whole grains, cereals, fruits, vegetables and legumes, you can incorporate all the different types of fiber into your diet. The functions of fiber vary with the type of fiber. The insoluble types act like sponges, holding water and cleaning your intestines as they pass through.