Bulking Up on Fiber
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Bulking Up on Fiber

image Fiber. You know you need to eat it. You are pretty sure it is good for you. But what is fiber, really? And why is it good for you?

What Are the Facts?

Fiber is found only in plants. It is from the plant cells, particularly the cell walls. The plant fiber that we eat is called dietary fiber. It is unique from other components of the plant because humans lack the enzymes necessary to digest it.

Dietary fiber is made up of two types of fiber: soluble and insoluble. Soluble means that when the fiber is mixed with a liquid, it forms a gel-like solution. Insoluble fiber does not mix with liquid and passes through the digestive tract largely intact. Both types of fiber help maintain bowel regularity.

Diets high in fiber have been associated with reduced risk of death due to cardiovascular disease (eg, heart attack and stroke), cancer, infections, and lung disease.

Soluble Fiber

When eaten as part of a low-fat, low-cholesterol diet, soluble fiber can help lower cholesterol and may help lower your risk of heart disease and strokes. Examples of foods high in soluble fiber include oatmeal, beans, peas, and citrus fruits.

Insoluble Fiber

Although insoluble fiber has not been shown to lower cholesterol, it is important for normal digestive health. Insoluble fiber speeds up movement through the small intestine and helps to alleviate constipation. Foods that are high in insoluble fiber include apple skin, All Bran cereal, wheat germ, and brown rice.

How Much Fiber Do I Need?

The American Dietetic Association recommends that women consume 25 grams of fiber daily, while men consume 38 grams. Fiber needs drop after the age of 50. Women older than 50 should consume 21 grams of fiber daily, and men should consume 30 grams daily. This includes both soluble and insoluble fiber. The following table lists how much fiber you can find in some common foods.

FoodServing size Total Fiber
Soluble FiberInsoluble Fiber
Broccoli, cooked½ cup1.510.5
Brussels sprouts, cooked½ cup4.53.01.5
Carrots, cooked½ cup2.511.4
Artichoke, fresh½ cup431
Apple1 medium413
Banana1 medium312
Blackberries½ cup413
Nectarine1 medium211
Citrus fruit (orange, grapefruit)1 medium2-311-2
Peach1 medium211
Pears1 medium422
Plums1 medium1.510.5
Prunes¼ cup31.51.5
Black beans, cooked½ cup5.523.5
Kidney beans, cooked½ cup633
Lima beans, cooked½ cup6.53.53
Navy beans, cooked½ cup624
Northern beans, cooked½ cup5.550.5
Pinto beans, cooked½ cup725
Lentils, cooked½ cup817
Peas, cooked½ cup615
Whole grain cereals
All Bran cereal1/3 cup80.77.3
Oatmeal, cooked½ cup211
Oat bran½ cup321
Shredded wheat2/3 cup30.32.7
Wheat germ2/3 cup817
Pearl barley, cooked½ cup523
Brown rice½ cup40.53.5
Psyllium seeds1 tablespoon651

Source: Journal of Family Practice

How Do I Increase the Amount of Fiber in My Diet?

It is easy to increase the fiber in your diet. It just takes a little thought and some action. Here are a few ideas to help you get on track to getting your daily recommended amount of fiber.

  • Try a whole grain cereal that contains at least 5 grams of fiber per serving. Slice a banana on top, or add some raisins or berries to increase the fiber even more.
  • Sprinkle a few teaspoons of wheat germ, ground psyllium, or ground flaxseed on your food.
  • Try eating some vegetables raw. Cooking can break down some of the fiber content. If you do cook vegetables, steam them lightly, so they are tender but still firm.
  • Leave the skin on fruits and vegetables. Just make sure you rinse them well with warm water to remove any dirt or bacteria.
  • Eat the whole fruit or vegetable instead of drinking the juice made from it. Juice does not contain the skin or membrane of the fruit or vegetable, and therefore its fiber content is substantially reduced.
  • Try adding whole, unprocessed grain to your diet. Substitute brown rice for white rice. Or opt for whole wheat bread or pasta.
  • Add beans to your soups, salads, and stews. Throw some beans on top of a salad or add lentils to soup while cooking.
  • Snack on fresh and dried fruit. Chomp some raisins or dried apricots in the afternoon, instead of a bag of potato chips or pretzels.


American Dietetic Association



Canadian Council on Food and Nutrition

Dietitians of Canada


Fiber. American Dietetic Association website. Available at: http://www.eatright.org/Public/content.aspx?id=6796&terms=fiber. Accessed February 3, 2011.

Fiber. American Heart Association website. Available at: http://www.americanheart.org/presenter.jhtml?identifier=4574. Accessed February 19, 2009.

Shamliyan T, Jacobs D, Raatz S, Nordstrom D, Keenan J. Are your patients with risk of CVD getting the viscous soluble fiber they need? Journal of Family Practice. 2006;9:761-769. EBSCO Consumer Health Complete website. Available at: http://www.ebscohost.com/thisMarket.php?marketID=14. Published September 2006. Accessed April 20, 2010.

3/28/2011 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance: Park Y, Subar AF, Hollenbeck A, Schatzkin A. Dietary Fiber Intake and Mortality in the NIH-AARP Diet and Health Study. Arch Intern Med. 2011 Feb 14. [Epub ahead of print]

Last reviewed February 2011 by Brian Randall, MD

Last updated Updated: 6/27/2011

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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