The below article is from the americanheart.org website:
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 (“bad”) cholesterol beyond levels achieved by a diet low in saturated and trans fats 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 can make you feel full, so you may eat fewer calories. 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.
Getting the right amount countsThe number of servings of grains that you need each day depends upon your age, gender and calorie needs. The recommended amount of grains that a particular person should consume daily is expressed in terms of “ounce-equivalents” but is commonly referred to as “ounces” (or servings) of grains.
A person who needs 2,000 calories each day to maintain a healthy body weight could eat 6 to 8 servings of grains (at least half of the servings should be whole-grain foods) and 8 to 10 servings total of vegetables and fruits (about ½ cup counts as a serving).
We recommend obtaining fiber from foods rather than from fiber supplements. Check the Nutrition Facts label on food packages to find foods with a higher amount of fiber. Try to get about 25 grams of fiber each day.
The following count as 1 ounce-equivalent (or 1 serving) of grains:
1 slice whole-grain bread (such as 100% whole-wheat bread)
1 ounce ready-to-eat, whole-grain cereal (about 1 cup wheat flakes)
1⁄2 cup cooked whole-grain cereal, brown rice, or whole-wheat pasta
5 whole-grain crackers
3 cups popped popcorn
1 slice white bread
1 small white roll
1 ounce ready-to-eat cereal (about 1 cup corn flakes)
1⁄2 cup cooked cereal, white rice, or pasta
9 mini 3-ring pretzels
1 4.5 -inch pancake
1 6-inch flour or corn tortilla
On a personal note if you are just starting to increase your fiber you would want to increase fiber slowly and not just decide one day that you are going to have 30 grams of fiber. Trust me.