What’s the Difference Between Soluble and Insoluble Fiber?

In the battle of the roughage, which one reigns supreme?

soup with beans carrots and other ingredients providing fiber

It’s best known for keeping your internal plumbing clear, but did you know that fiber actually has health benefits that go beyond helping you stay regular?

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“Fiber is an important nutrient that comes from plants. It’s sometimes called roughage or bulk,” says registered dietitian Gillian Culbertson MS, RD, LD.

Fiber comes in two forms: soluble and insoluble. Getting the right amount of both can aid digestion and may even lower your risk for certain chronic diseases.

What is soluble and insoluble fiber?

When you eat, your body breaks food down into nutrients it can use. But it can’t digest or absorb fiber, which is actually a good thing. Instead, fiber stays mostly intact for its journey through your body.

Soluble fiber dissolves in water and other body fluids. When it does, it forms a gel-like material as it passes through. Once it makes it to the colon, it feeds your good gut bacteria. Healthy gut bacteria are linked to a host of health benefits, including some protection against obesity and its related conditions, such as diabetes.

Insoluble fiber doesn’t dissolve in fluids. Instead, it absorbs them and sticks to other materials to form stool. This process leads to softer, bulkier — and more regular — stools.

How fiber benefits your body

Both kinds of fiber are essential for your health. Fiber’s benefits include:

Benefits of soluble fiber

The gel-like substance that soluble fiber creates in your body:

Benefits of insoluble fiber

How to get more soluble fiber in your diet

Good sources of soluble fiber include:

“Reach for these foods when you need a snack, or add them to soups, salads and other meals,” Culbertson suggests.

How to get more insoluble fiber in your diet

Good sources of insoluble fiber include:

“Since most plants have both forms of fiber, you get more bang for your buck when you eat a diet rich in vegetables,” Culbertson says. “Breakfast can be a great time to get insoluble fiber through high-fiber cereals and oatmeal. You can also use whole-wheat flour instead of white flour in some recipes.”

How much fiber do you need?

There’s no need to track soluble vs. insoluble fiber intake — instead, focus on the total amount of fiber you eat daily. Here are the recommended amounts:

Check nutrition labels to track how much fiber you’re eating. And if you’re one of the many Americans who don’t get enough, start slowly and work your way up, Culbertson recommends. Too much fiber too soon can lead to gas pain and bloating.

“Eating a diet rich in a variety of whole foods, including fruits, vegetables and legumes, is a great place to start,” Culbertson says. “And while you may occasionally benefit from a fiber supplement, food is always going to be the best source.”