Some of fiber’s greatest benefits are related to cardiovascular health. Several large studies have found that people who eat the most fiber had a lower risk for heart disease. High fiber intake—particularly soluble fiber—seems to protect against several heart-related problems. . . . Fiber can help relieve constipation and normalize your bowel movements. Insoluble fiber is often used to treat or prevent constipation and diverticular disease, which affects the large intestine, or colon. Fiber may also play a role in reducing the risk for type 2 diabetes, the most common form of diabetes. Fiber in the intestines can slow the absorption of sugar, which helps prevent blood sugar from spiking.