Dietary fiber is the indigestible part of plants. Fiber is important for a healthy gastrointestinal (GI) system because it helps to soften and plump the stool to make it easier to pass, thereby helping the digestive system function more effectively. Dietary fiber helps prevent both constipation and diarrhea, because it simultaneously bulks up stool while solidifying watery stool.
Fiber also assists in weight loss in several ways. For one, fiber makes an individual feel fuller longer. Also, meals with more fiber provide more food with fewer calories, because the fiber adds bulk without energy.
In addition, a diet high in fiber may also lower the risk for hemorrhoids and colon disease.