Dietary Fiber: Insoluble and Soluble Fiber

January 24, 2013

By Tiana Yom

Are you getting enough fiber in your diet?

We have all heard of fiber-rich foods and high-fiber diets. You may think of dry, tasteless, cardboard-like bran flakes or crackers when you hear the word fiber, but there are a lot of fiberous foods that are full of flavor. What exactly is fiber, and why is it vital to include it in our diets?

Dietary fiber is the part of plant foods that our bodies cannot digest or absorb. This indigestible ‘bulk’ is very important to have in our diets because it helps the digestion process from start to finish. Furthermore fiber slows the absorption of sugar into our bloodstreams to help maintain stable blood sugar levels and help prevent type 2 diabetes.

There are two types of fiber: insoluble and soluble.

Insoluble fiber is mainly made up of plant cell walls and acts like a sponge. These fibers do not dissolve in water, so they absorb water as they pass through the gastrointestinal (GI) tract, and speed up the passage of food and waste through your gut. Insoluble fiber helps clean out the colon and regulate bowel movements.

Examples of insoluble fiber: Whole wheat, whole grains, wheat bran, corn bran, seeds, nuts, barley, couscous, brown rice, zucchini, celery, broccoli, cabbage, onions, the skin of fruits like pears and apples, tomatoes, carrots, cucumbers, green beans, dark leafy vegetables, raisins, potatoes, and cauliflower.

Soluble fiber dissolves in water and creates a gel-like substance. This gel works to helps you feel full, control blood sugar, and reduce the LDL, or unhealthy, cholesterol.

Examples of soluble fiber: Oatmeal, lentils, the inside of fruits like apples, oranges, pears, and prunes, oat bran, strawberries, nuts, flaxseeds, beans, chickpeas, dried peas, blueberries, cucumbers, celery, carrots, and Brussels sprouts.

Recap: Insoluble fiber helps with digestion, whereas soluble fiber helps with controlling blood sugar and reduces cholesterol levels.

What fiber-rich foods can you eat?

For breakfast, try whole grain cereal with a cup of strawberries and flaxseeds.

For lunch and/or dinner, you can have brown rice with poached salmon and Brussels sprouts. This meal provides both fiber (brown rice and brussel sprouts) and omega-3s (salmon).

How much fiber do you need per day?

If you’re 50 and younger:

  • Women: 25 grams
  • Men: 38 grams

If you’re 51 and older:

  • Women: 21 grams
  • Men: 30 grams

What high-fiber foods do you eat?


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  1. I love this article! It’s well-written and very informative. I never knew that there two types of fiber and thanks for the meal suggestions. I will be making brown-rice and salmon tonight!

    1. Glad you enjoyed the post Brittany! It’s important to have both types of fiber as you can see from the great benefits of them!

  2. Oh, how could I forget about good ol’ beets and okra? Wesley, how do you prepare these wonderful sources of fiber?

  3. My wife was telling me that we need more fiber in our diets and was curious about the different kinds. I really like the sound of soluble fiber, because it’s dissolved in water, and is good for blood sugar! Since we like to control our sugar intake, it would be nice to have that option to help the sugar in our blood.