Fiber is important to a healthy diet, but many Americans aren't getting enough of it. Most women under 50 are getting about 40 percent less fiber than they should. And men are even worse, getting only about half the recommended amount.
Fiber-rich foods can also be a source of important nutrients, such as B vitamins, selenium and magnesium.
Bob Greene, author of "The Best Life Diet Cookbook," has the lowdown on fiber -- how much you need, easy ways to increase your fiber intake, and some surprising fiber-boosting foods you may not have known about.
50 and younger
Men: 38 grams
Women: 25 grams
Eat high fiber cereals for breakfast. You can rack up one-third to one-half your daily fiber requirement in a 160-calorie bowl, because a lot of these high-fiber options have the added benefit of being low in calories. You want to stick to cereals that have at least 5 or 6 grams per serving.
Some high-fiber cereals include All Bran, Uncle Sam, Kashi Go Lean, Nature's Path Optimum Slim, Nature's Path Flax Plus, raisin bran and Special K Protein Plus.
Beans are a great source of fiber as well as other important vitamins and minerals. Black beans, lentils, pinto beans, garbanzo beans, red kidney beans and chickpeas are all great and can be easily incorporated into your diet.
Eat whole grain versions of staple foods. Eat brown rice, whole wheat pasta (or as an interim step, have a fiber-enriched or partially whole wheat pasta), barley, bulgur wheat and quinoa, and use whole grain crackers and bread.
One-hundred percent whole wheat breads, tortillas, English muffins and pitas contain twice the fiber and almost half the calories of their all-white counterparts.
Some products include Wasa Crispbread (multigrain, hearty rye and fiber rye are all good choices), Barilla whole grain pasta, Flatout flatbread multigrain wrap, Peppperidge Farm 100% Natural and 100% Whole Wheat Reduced Sodium Bread.
Fruits and Vegetables. You get better fiber when you see strings in a vegetable -- that's the cellulose or fiber. When you look at a broccoli stalk or an artichoke, you can see the fiber. Pears have five grams of fiber, compared to that old standby the prune, which has three grams.
Raspberries are also a good option. One cup of antioxidant-rich raspberries has 8 grams of fiber and only 60 calories. Try adding berries to high-fiber cereal. Best of all, you can eat them as a dessert.
But don't just eat the same things over and over. It's wise to diversify. Eat a variety so that you take in as many nutrients as possible. And try to go seasonal with fruits and vegetables when they taste the best. In season now are grapefruit, oranges, grapes, apples, pears, strawberries (in Florida), broccoli, cauliflower, carrots and butternut squash.
And think twice about peeling fruits and vegetables like apples, potatoes and cucumbers, because the peels have much of the fiber.
Nuts and seeds are probably the easiest thing to mix into your food for that extra kick, but they can be high in calories, so stick to about one ounce a day.
Not only are nuts rich in fiber, but also in good fats, and phytonutrients found in nuts have been linked to reduced risk of heart disease.
Pistachios have the least amount of calories and fat of all nuts, and a one-ounce serving has 3 grams of fiber. Toss pistachios into your cereal or yogurt, on top of salads or eat them on their own as a fiber and protein-packed snack.
Bob Greene has a special called "What's Making You Fat: A Best Life Special" airing on Discovery Health, Thursday, March 26 at 8 p.m. Find out more at www.discoveryhealth.com.
Greene also has a new program called the Move Campaign to help people suffering from osteoarthritis manage joint pain and stiffness, as well as the overall impact of the disease with low-impact movement and exercises.