The numbers are clear: Americans aren’t getting enough fiber.

Research has consistently shown that high-fiber diets are linked to significant health benefits, including a lower risk of cardiovascular disease and colorectal cancer, as well as improved arthritis symptoms.

Despite these benefits, there remains a significant fiber gap in the typical American diet. The recommended daily fiber intake is 25 grams a day for women and 38 grams a day for men. From 2013 to 2018, only 4% of U.S. adults met their recommended adequate intake for dietary fiber. The average fiber intake was about 16 grams a day.

Adding fiber to your diet through eating more fiber-rich foods or by taking fiber supplements has become a viral health trend. At the same time, the 2025 update to the American dietary guidelines appears to downplay fiber’s role in a healthy diet, placing high-fiber whole grains at the bottom as the smallest part of the inverted food pyramid. This can be confusing, because the written guidelines themselves continue to highlight the importance of eating whole grains.

What does the science say about the health benefits of a high-fiber diet? And what steps can you take to incorporate more fiber into your diet? These and similar questions my patients have asked me as a physician-scientist prompted me to look further into the latest research on dietary fiber.

Basics of dietary fiber

Dietary fiber can be found in many sources, and the choices can be overwhelming.

Dietary fiber refers to carbohydrates your body can’t digest. Many whole foods are high in fiber. High-fiber foods include raspberries, avocados, oats and other whole grains, and lentils and other legumes.

Fiber also........

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