25-30 grams of fiber is recommended for adults. Here's a nice blurb from the American Heart Association's website (www.americanheart.org
"Dietary fiber is the term for several materials that make up the parts of plants your body can't digest. Fiber is classified as soluble or insoluble.
When eaten regularly as part of a diet low in saturated fat, trans fat and cholesterol, soluble fiber has been associated with increased diet quality and decreased risk of cardiovascular disease. Soluble or viscous fibers modestly reduce LDL cholesterol beyond levels achieved by a diet low in saturated and trans fatty acids and cholesterol alone. Oats have the highest proportion of soluble fiber of any grain. Foods high in soluble fiber include oat bran, oatmeal, beans, peas, rice bran, barley, citrus fruits, strawberries and apple pulp.
Insoluble fiber has been associated with decreased cardiovascular risk and slower progression of cardiovascular disease in high-risk individuals. Dietary fiber may promote satiety by slowing gastric emptying, leading to an overall decrease in calorie intake. Foods high in insoluble fiber include whole-wheat breads, wheat cereals, wheat bran, rye, rice, barley, most other grains, cabbage, beets, carrots, Brussels sprouts, turnips, cauliflower and apple skin.
Many commercial oat bran and wheat bran products (muffins, chips, waffles) contain very little bran. They also may be high in sodium, total fat and saturated fat. Read labels carefully."