Americans are not consuming enough dietary fiber, despite its proven health benefits, which include reducing the risk of cardiovascular disease and colorectal cancer, and improving arthritis symptoms.
Read More
The recommended daily fiber intake is 25 grams for women and 38 grams for men. However, from 2013 to 2018, only 4% of U.S. adults met these recommendations, with average consumption around 16 grams per day.
Increasing fiber intake has become a popular health trend, yet the 2025 update to American dietary guidelines places high-fiber whole grains at the smallest segment of the inverted food pyramid, which can lead to confusion. Despite this visual representation, the guidelines still emphasize the importance of whole grains.
Dietary fiber consists of carbohydrates that the body cannot digest and can be found in many whole foods, including fruits like raspberries and avocados, grains, and legumes. Fiber supplements, such as psyllium husk powder (Metamucil), are also available. Notably, different types of fiber serve various functions in the body. For instance, viscous fibers like psyllium can promote feelings of fullness, lower cholesterol, and improve blood sugar levels. Fermented fibers, such as inulin from chicory root, support gut bacteria that can help reduce inflammation.
In addition to fiber, probiotics—found in foods like yogurt and kimchi—can also enhance gut health. Probiotics introduce beneficial bacteria into the gut, while fiber provides food for the existing bacteria. A 2021 study suggested that those on a high-fiber diet had a more active gut microbiome when it came to breaking down fiber, while those consuming fermented foods exhibited higher diversity in gut bacteria and lower inflammation levels.
To increase fiber intake, experts recommend doing so gradually, allowing the body time to adjust while maintaining hydration. Barriers such as cost and the potential for digestive discomfort from some fibers can deter people from increasing their fiber intake. Individuals should explore different fiber sources to find what suits them best, as there is no universal approach to a healthy diet.
Research is ongoing to clarify the specific benefits of various fiber types, including optimal doses and combinations. While some observational studies have linked higher whole grain intake to lower arthritis risk, further clinical trials are necessary to substantiate these findings. Ultimately, while the health benefits of fiber are well-established, public education, affordability, and accessibility are crucial for increasing fiber consumption among Americans.
Jean Liew, Assistant Professor of Medicine, Boston University