William Beaumont noted the gastric effects of vegetable fiber and suggested that dietary fiber may provide health benefits. In the last decade investigators documented the physiological effects of fiber on gastric emptying, intestinal nutrient absorption rates, and colon function. Further clinical investigation and much more of the type of repetitive observations pioneered by Beaumont are required to definitively establish the physiological effects of fiber on gastrointestinal physiology. High-fiber intake provides well-established benefits for persons with diabetes: it lowers insulin requirements, provides better control of blood glucose, and reduces serum lipids. Foods rich in soluble fiber, such as oat or bean products, lower cholesterol significantly for persons with hypercholesterolemia and for healthy young subjects. High-fiber foods also lower serum triglycerides and blood pressure. Several studies indicate that high intake of fiber protects against coronary heart disease.