The health benefits of fiber are well documented in reducing the risk of certain diseases. Fiber is linked to reduced risk of cancer, especially colon and breast cancer, and fiber may help lower LDL cholesterol (bad cholesterol) and total cholesterol levels, which can reduce your risk of heart disease. Soluble fiber, in particular, also can help in the management of diabetes by reducing blood sugar.

Fiber can absorb large amounts of water in the bowels, and this makes stools softer and easier to pass. Anyone starting a higher-fiber diet will notice the difference in stool bulk.

In almost all cases, increasing fiber in the diet will relieve constipation within hours or days. Because stools are easier to pass, less straining is necessary, and this can help relieve hemorrhoids.

Evidence has shown that foods containing soluble fiber (such as oats, rye barley, and beans) can have a positive influence on cholesterol, triglycerides, and other particles in the blood that affect the development of heart disease. Some fruits and vegetables (such as citrus fruits and carrots) have been shown to have the same effect.

The passage of food through the body is speeded up when fiber is eaten. Some experts believe this may prevent harmful substances found in some foods from affecting the colon and may protect against colon cancer. Other types of cancer that are linked with over-nutrition and may be prevented by a fiber-rich diet include breast cancer, ovarian cancer, and uterine cancer.

Adding fiber to the diet helps regulate blood sugar levels, which is important in avoiding and controlling diabetes through a significant reduction in their blood sugar levels and reduction their medication.

Additional Resources:
http://www.wholegrainscouncil.org/whole-grains-101/what-are-the-health-benefits