Fiber rich diets protect against heart disease, colon cancer, and diabetes. The protective effects result from a high fiber diet (not one magic food). Including dietary fiber has been shown to result in decreased food energy intake, including fat, cholesterol, and sugar. Hence, fiber aids in weight control.
Fiber improves large intestine function by maintaining the integrity of the intestinal cell wall. It speeds up transit time and stimulates microbial digestion of absorbable products. This helps to alleviate or prevent constipation.
Populations consuming high-fiber diets generally have lower rates of colon cancer than similar populations consuming low-fiber diets. Fiber may prevent colon cancer by diluting, binding, and rapidly removing potentially cancer-causing agents from the colon.
Fiber also lowers blood cholesterol levels by binding with bile, the emulsifier that assists with fat and cholesterol absorption. With less bile available, fat and cholesterol absorption diminishes and blood cholesterol concentrations decline.
Fiber can help in diabetes by slowing glucose absorption rate. Soluble viscous fibers can trap nutrients and delay their leaving the stomach; hence, fiber delays absorption and elicits a moderate insulin response and a moderate rise in blood glucose.