10 Amazing Health Benefits of Fiber
You know you're supposed to eat plenty of fiber (28-34 grams per day to be exact, per the 2020-2025 Dietary Guidelines for Americans), but if you're among the 90-97% of Americans not getting enough of it in your diet, you're missing out on a slew of health benefits. Here are 10 of fiber's health benefits to encourage you to get your fill.
1. Healthy Weight Loss
It is well-known increasing your dietary fiber intake may help in your weight loss journey. In a 2019 randomized controlled trial published in The Journal of Nutrition, participants were randomly assigned to one of four different calorie-restricted dieting groups. They were also instructed to increase their dietary fiber intake at various intervals and to include 90 minutes of physical activity each week. Results showed that regardless of diet type, participants lost about the same amount of weight. Study authors felt this was due to the fiber intake, which affirms what previous studies had shown—that increasing your fiber intake can help you lose weight.
Fiber-rich foods fill you up faster and keep you satisfied longer.
2. Weight Maintenance
While more research needs to be performed, there is some evidence that suggests that those who eat more fiber tend to be leaner, according to a 2017 study in The Journal of Nutrition and Metabolism. Researchers compared two groups, one that was considered normal-weight and one that was classified as obese, and found that those who were considered normal-weight ate more fiber than those who fell into the obese category.
3. Lower Type 2 Diabetes Risk
A 2020 study published in the Journal of Diabetes Investigation found that a higher overall intake of dietary fiber was associated with a lower risk of type 2 diabetes. And while some previous studies showed that insoluble fiber was the fiber star regarding type 2 diabetes, this study suggests that the combination of soluble and insoluble fiber predicted greater prevention of type 2 diabetes. While it's not totally clear why fiber cuts type 2 diabetes risk, the researchers believe that it could be a combination of fiber's favorable effect on blood glucose levels, creating a healthier gut microbiome and lowering inflammation in the body that may help stave off the development of diabetes.
4. Lower Odds of Heart Disease
A 2017 review in the Journal of Chiropractic Medicine shows a strong correlation between high fiber intake and reduced risk of cardiovascular disease and stroke, as well as dying from cardiovascular disease. That's partly due to fiber's ability to sop up excess cholesterol in your system and ferry it out before it can clog your arteries. In particular, this review found that fiber in the form of beta-glucan (6 grams/day) and psyllium (10 grams/day) showed significant benefits regarding the reduced risk of heart disease. Both of these fibers are forms of soluble fiber. Beta-glucan is found in oats and barley. Psyllium comes from the husks of the psyllium seed and is used in dietary fiber supplements and added to baked goods to increase the fiber content of the product.
5. Increased Beneficial Gut Bacteria
The good bacteria that make up your gut's microbiome feed off fiber and help them flourish. According to a 2022 review article in Animal Nutrition, as your gut bacteria gobble up fiber that has fermented in your GI tract, they produce short-chain fatty acids that have a host of benefits—including lowering systemic inflammation, which has been linked to nearly every major chronic health problem.
When you increase your fiber intake, it doesn't take long to see the results. "You can start to see the changes in gut bacteria within just a few days," says Kelly Swanson, Ph.D., a professor of nutritional sciences at the University of Illinois at Urbana-Champaign. The catch: You've got to consistently get enough grams of fiber over time to keep getting the benefits. Skimping on fiber shifts bacteria populations that may have negative consequences and result in increased inflammation in the body.
6. Reduced Risk of Certain Cancers
While studies are mixed, most seem to point to higher fiber consumption lowering the risk of cancer, especially colorectal and breast cancers. For example, in a 2020 review in The American Journal of Clinical Nutrition, researchers found that higher fiber intake, in particular, the fiber found in whole grains, was correlated with a reduced risk of colorectal cancer. And another 2020 review published in Cancer found that soluble fiber and fruit fiber had the strongest associations with reduced risk of breast cancer. This falls in line with the American Cancer Society's recommendations to eat foods rich in total fiber, which include fruits, vegetables and whole grains.
7. Longer Life
A 2022 review in the Journal of Translational Medicine found that people who ate enough total fiber—which includes soluble and insoluble fibers—had a lower chance of dying from anything, including cardiovascular disease and cancer. This means that even if you were to get heart disease, cancer, or another condition, consuming enough fiber may protect you from dying from it.
8. More Regular Bowel Movements
"Constipation is one of the most common GI complaints in the United States," says Tanya Zuckerbrot, RD, author of The F-Factor Diet. If you find yourself constipated, fiber might help. Fiber makes your poop softer and bulkier—both of which speed its passage from your body. But different types of fiber may provide varying levels of success in your quest for more regular bowel movements. A 2020 review in the Journal of the American Association of Nurse Practitioners suggests that psyllium fiber beats out other types of fiber for those with chronic idiopathic constipation, which is characterized by difficult, infrequent, or incomplete bowel movements. Other studies, like the 2021 review in Clinical and Experimental Gastroenterology note that including plenty of water with your high-fiber diet also helps move things along in your gut better than fiber alone.
9. All-Natural Detox
Forget the trendy juice cleanse fads. Fiber naturally scrubs and promotes the elimination of toxins from your GI tract. "Soluble fiber soaks up potentially harmful compounds, such as excess estrogen and unhealthy fats, before they can be absorbed by the body," explains Zuckerbrot. And because insoluble fiber makes things move along more quickly, it limits the amount of time that chemicals like BPA, mercury and pesticides stay in your system, adds Zuckerbrot. The faster they go through you, the less chance they have to cause harm.
10. Strong Bones
Some types of soluble fiber—known as prebiotics—have been shown to increase the bioavailability of minerals, like calcium, in the foods you eat. The increase in bioavailability may help maintain bone density, according to a 2018 review in the journal Calcified Tissue International. Prebiotics provide food for your beneficial gut bacteria and can be found in certain fruits, vegetables, nuts and whole grains, such as asparagus, bananas, walnuts, onions, legumes, wheat and oats.
The Bottom Line
As you can see, fiber—all types—is good for your health. By eating a well-rounded, balanced diet that includes plenty of fruit, vegetables, nuts, seeds, legumes and whole grains, you will likely get the amount of fiber your body needs to run efficiently and lower your disease risk.
This article first appeared in EatingWell, March/April 2016.