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The facts about fiber

A woman shopping for sweet potatoes in a grocery store.

If you're not getting enough fiber in your diet, you're missing out on some big health benefits.

Life is better when everything is running smoothly.

Your car is cruising along fine. Work is flowing on the job with few problems. But you…well, maybe things aren't moving quite as well as they should be.

Maybe you need more fiber in your diet.

Fiber isn't your typical nutrient. Unlike vitamins or minerals, fiber doesn't enrich your body by depositing healthy goodness in cells or tissues. Instead, much of it passes through your digestive system nearly intact. Fiber goes in, fiber goes out.

In its travels, fiber helps move waste, lower cholesterol and reduce risk of disease—possibly even some cancers.

Fiber and its forms

Dietary fiber comes in two forms: soluble and insoluble.

Insoluble fiber does not dissolve in water. It's the bulky fiber that keeps things moving through your colon. Insoluble fiber reduces your risk for constipation and bowel diseases like diverticulosis. It's found in whole grains, wheat cereals and vegetables such as carrots, celery and tomatoes.

Soluble fiber, on the other hand, does dissolve. It turns into a gel-like substance and helps control blood sugar levels and reduce cholesterol. Sources of soluble fiber include barley, oatmeal, beans, nuts, and fruits like apples, berries, citrus fruits and pears.

In general, the more refined or processed a food is, the less fiber it provides. For example, one medium apple with the peel contains 4.4 grams of fiber, notes the Academy of Nutrition and Dietetics. A half cup of applesauce provides 1.4 grams of fiber. And 4 ounces of apple juice contains no fiber at all.

Many foods contain both soluble and insoluble fibers. However, fiber is only found in plant foods. Dietary fiber is not found in foods from animals, such as beef, poultry, eggs and fish.

Fitting fiber in your life

The National Academies of Sciences, Engineering and Medicine recommends women from ages 19 to 50 get 25 grams of dietary fiber daily, and 21 grams after age 50. Men should get 38 grams through age 50, and 30 grams after age 50. But how do you find it, and how do you fit it into your life?

Good sources of fiber include:

  • 1 large pear with skin, 7 grams.
  • 1 cup fresh raspberries, 8 grams.
  • ½ medium avocado, 5 grams.
  • 1 ounce almonds, 3.5 grams.
  • ½ cup cooked black beans, 7.5 grams.
  • 1 cup cooked pearled barley, 6 grams.
  • 1 medium orange, 3.1 grams.
  • 1 medium banana, 3.1 grams.
  • ½ cup whole-wheat spaghetti, cooked, 2.3 grams

You can fit fiber in your life by adding a few more fruits and vegetables to your diet. And that isn't too difficult. You can mix oats into meatloaf, bread or other baked goods. You could toss beans and cut vegetables into your next salad or soup. Or chop up veggies to add to pasta or stir-fry dishes.

When you buy breads and pasta, look for the words 100% whole grain. And choose brown rice over white.

Things to consider

When it comes to fiber, it is possible to have too much of a good thing. Excessive amounts of fiber can cause gas, constipation and other problems.

As you add fiber to your diet, do so slowly. It's also important to increase how much water you drink. Too little water can lead to constipation.

It's best to seek your dietary fiber from foods instead of supplements. A supplement isn't going to provide all the same nutritional benefits as natural fiber.

And read nutrition labels on breads, pasta and other products to see how much fiber is in each serving. Just because a bread is darker in color doesn't mean it contains more fiber.

Reviewed 1/6/2021

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