Patient education: High-fiber diet (The Basics)

What is fiber? — Fiber is a substance found in some fruits, vegetables, and grains. Most fiber passes through your body without being digested. But it can affect how you digest other foods, and it can also improve your bowel movements.

There are 2 kinds of fiber. One kind is called "soluble fiber" and is found in fruits, oats, barley, beans, and peas. The other kind is called "insoluble fiber," and is found in wheat, rye, and other grains.

Both kinds of fiber that you eat are called "dietary fiber."

Why is fiber important to my health? — Fiber can help make your bowel movements softer and more regular. Adding fiber to your diet can help with problems including constipation, hemorrhoids, and diarrhea. Plus, it can help prevent "accidents" if you have trouble controlling your bowel movements.

Getting enough fiber can also help lower your risk of heart disease, stroke, and type 2 diabetes. That's because fiber can help lower cholesterol and help control blood sugar.

How much fiber do I need? — The recommended amount of fiber is 20 to 35 grams a day. The nutrition label on packaged foods can show you how much fiber you are getting in each serving (figure 1).

How can I make sure I'm getting enough fiber? — To make sure that you're getting enough fiber, eat plenty of the fruits, vegetables, and grains that contain fiber (table 1 and figure 2). Many breakfast cereals also have a lot of fiber.

If you can't get enough fiber from food, you can add wheat bran to the foods you do eat. Or you can take fiber supplements. These come in the form of powders, wafers, or pills. They include psyllium seed (sample brand names: Metamucil, Konsyl), methylcellulose (sample brand name: Citrucel), polycarbophil (sample brand name: FiberCon), and wheat dextrin (sample brand name: Benefiber). If you take a fiber supplement, be sure to read the label so you know how much to take. If you're not sure, ask your doctor or nurse.

What are the side effects of fiber? — When you start eating more fiber, your belly might feel bloated, or you might have gas or cramps. You can avoid these side effects by adding fiber to your diet slowly.

Some people feel worse when they eat more fiber or take fiber supplements. If you feel worse after adding more fiber to your diet, you can try decreasing the amount of fiber to see if that helps.

More on this topic

Patient education: Diet and health (The Basics)
Patient education: Constipation in adults (The Basics)
Patient education: Diarrhea in adolescents and adults (The Basics)
Patient education: Hemorrhoids (The Basics)
Patient education: Fecal incontinence (The Basics)

Patient education: High-fiber diet (Beyond the Basics)
Patient education: Diet and health (Beyond the Basics)
Patient education: Constipation in adults (Beyond the Basics)
Patient education: Chronic diarrhea in adults (Beyond the Basics)
Patient education: Hemorrhoids (Beyond the Basics)
Patient education: Fecal incontinence (Beyond the Basics)
Patient education: Type 2 diabetes and diet (Beyond the Basics)