Fiber is the most complex of carbohydrates, often forming the structural elements of plants. Fiber is relatively indigestible by humans, but is still an extremely important part of your diet. Insoluble fiber provides bulk, which helps to move food residues through your digestive system. But some fiber — soluble fiber — also has beneficial physiological effects.
The most accepted benefit of soluble fiber is in lowering bad LDL cholesterol levels — oat bran is well recognized for this benefit, and beans are a tasty source of soluble fiber, too.
Specific benefits to health from the fiber component of your diet are challenging to isolate because foods that offer fiber are also rich in biologically active phytochemicals and antioxidants. But having adequate fiber in your diet may lower blood pressure, reduce the risk for some colorectal and breast cancers, improve your immune system, and improve blood glucose control.
Americans typically consume only about 15 grams of fiber per day, but the recommended daily consumption is 25 grams for women between 19 and 50 years of age, and 38 grams per day for men in that age range. The recommended amount decreases for both men and women over 50, but the more the merrier.
While a huge volume of fiber could lead to digestive irritation, if you can tolerate more fiber, get more fiber.
Fiber only comes with plant-based foods, but you can increase your fiber consumption by making different choices. For instance, white bread from refined flour only contains one third the fiber of whole wheat bread — brown rice contains almost six times more fiber as white rice. Oatmeal, beans, and peas are excellent sources of fiber too.
Remember that grains, beans, and peas are also starchy, and need to be accounted for in your diet to control blood glucose.
Nonstarchy vegetables, while not necessarily high in fiber, are very low in carbohydrate, and come with a load of assrted nutrients as well. These foods can, and should, be eaten liberally for their nutrition content, their modest effect on blood glucose due to their low carbohydrate content, and for adding more fiber to your daily intake.