High fiber diets can help lower the risk of heart, or cardiovascular, disease. Fiber helps to regulate blood pressure. The two types of fiber are soluble and insoluble. Soluble fiber absorbs water during digestion while insoluble fiber does not. Soluble fiber is found in fruits, barley and oats. Insoluble fiber is found in many foods, including vegetables, whole grains and cereals. Many packaged foods that now have added fiber, but fiber should not come mainly from supplements. Most people need 25 to 30 grams of fiber per day from food.