With shifts in the American diet over the last few decades, it’s not surprising that the average American only consumes about 15 grams of fiber daily, well below the recommended amount.
Though it’s long been known that a high-fiber diet may help with intestinal regularity, recent research also notes that it can improve heart health by lowering cholesterol levels and “bad fats,” along with helping to control blood sugar. Fiber’s bulk also provides a feeling of fullness, which can help with weight management and boost your body’s microbiome.
“When you digest something rich in fiber, your body has to do more work,” says Olivia Mathisen-Holloman, registered dietitian with Kaiser Permanente in Seattle. “Fiber acts as a super-delicious food source for the different microbes living inside your gut that do the work of gut health.”
Moreover, fiber-loving microbes encourage a brain-gut connection through serotonin, a chemical that helps regulate emotions like joy.
“The microbiota stimulates different cross-fermentation actions and supports the creation of transmitters,” she says. “There’s a bidirectional communication between your gastrointestinal tract and the brain.”
Experts recommend that men ages 19 and older aim for 38 grams of fiber daily, while women ages 19 and older aim to get in 25 grams.
Without the right amount of fiber, Mathisen-Holloman says, you’ll likely first notice issues with your bowel habits. “A healthy bowel movement routine is important,” she says. “Bowel movements are a key indicator of health.”
While most people struggle to get enough fiber into their diet, a diet with too much fiber (around 50-60 grams a day or more) can make it harder to absorb vitamins and minerals. Working with a doctor or registered dietitian can help you find the right balance.
Have trouble staying consistent with fiber intake? “There are resources available through the USDA,” Mathisen-Holloman says, which maintains a helpful Food Sources of Dietary Fiber website.
Familiarize yourself with fiber
The key to fiber is maintaining a consistent diet. “Berries are an incredible resource, as are stone fruits, apricots and plums — all great sources of fiber,” says Mathisen-Holloman.
Fiber is found in:
- Grains: Whole grains, oatmeal, popcorn, whole wheat bread and pasta.
- Legumes: Including lentils, black beans and soybeans.
- Fruits: Including guava, pears and apples with skin.
- Vegetables: Including carrots, broccoli, green peas and collard greens.
- Nuts: All types.
Foods with little or no fiber include most fast foods, meats, and prepared and processed foods.
For some rough estimates, a cup of raspberries contains 8 grams of fiber. A cup of boiled pinto beans contains almost 16 grams of fiber. Brown rice and whole-grain products generally contain more fiber than refined or processed products.
Preparation matters too. A medium boiled potato serves up 2 grams of fiber, while the same potato, baked with skin on, offers 5 grams.
Fiber types
Fiber comes in two forms, and you need both as part of a balanced diet.
Soluble fiber can be found in many fruits and plant foods and becomes gel-like when it mixes in your digestive system. This gel helps control blood sugar and reduce cholesterol, particularly “bad” cholesterol.
Insoluble fiber is found in more of the tougher, chewier parts of plants and vegetables, such as apple peels. It acts like a cleansing brush, gently scrubbing out the colon as the fiber passes through the digestive tract. It remains solid as it does so, helping with bowel regularity.
Some foods contain both types. A small apple has 2.8 grams of fiber, Mathisen-Holloman says. One gram is soluble fiber, and 1.8 grams is insoluble fiber. Beans are another good source of both types of fiber.
Use caution when purchasing over-the-counter assistance, however, as fiber in constipation products may not be as helpful to your overall system. “The synthetic fibers aren’t as valuable for the gut because they don’t work the same way,” says Mathisen-Holloman.
Fiber tips for everyone
“Dietitians help people strike a balance,” she says. “Balance is essential to keep things moving. Too much of anything, or an all-or-nothing mentality regarding food and nutrition, can be hard to navigate and manage.”
A few tips for adding fiber to your diet:
- Add fiber to every meal: Include one fiber-rich food at breakfast, lunch and dinner. This might include oatmeal or berries with breakfast or beans in tonight’s salad, soup or casserole dinner.
- Challenge your assumptions: “I encourage clients to challenge their beliefs about fruits and vegetables,” Mathisen-Holloman says. Some foods can be “victims of poor preparation” in childhood, leading to continued dislike as an adult. Try new preparation methods.
- Get creative with fiber-rich foods. Toss in wheat bran or carrots to your muffins or find other ways to boost fiber without interfering with flavor.
- Drink water: Fiber works best when paired with water.
- Keep the peels on: For max fiber, don’t peel fruits and veggies.
- Snack smart: Keep healthy, fiber-rich foods on hand, like fresh berries and whole-grain crackers.
- Go slow: Too much fiber too fast can lead to constipation. Level up your fiber intake slowly.
Prioritizing your health makes a lasting difference. Your Kaiser Permanente care team and health plan are here to support your care at all our locations, including our newly expanded Everett Medical Center. Visit kp.org to learn more.