Key Takeaways
- Eating enough fiber may lower your risk of death from heart disease, cancer, and other causes.
- Eat fiber regularly to support healthy gut bacteria and protect your gut barrier.
- Eat a mix of soluble and insoluble fiber from plant foods, such as vegetables, beans, fruits, and whole grains.
Most Americans don’t get enough fiber, and, frankly, the nutrient could use a rebrand. Some people on social media have taken matters into their own hands, coining the term “fibermaxxing,” which basically means eating more fiber—ideally, 25 to 35 grams daily, depending on your calorie needs.
While fiber is widely known for its digestive benefits, eating enough of it on a regular basis also supports gut health, reduces your risk of chronic disease, and helps you live a healthier, longer life.
We spoke with our chief medical officer, Sohaib Imtiaz, MD, who is board-certified in lifestyle medicine, for his take on fibermaxxing and to explain how fiber impacts longevity.
*This interview has been edited and condensed for clarity.
Q: What does fiber have to do with longevity? How can it help you live healthier now and extend your life in the future?
Imtiaz: We have data showing that adequate fiber intake reduces the risk of death from any cause or from specific diseases, like heart disease and cancer, but you have to consider its impact on gut health to understand how it reduces your risk.
Your dietary fiber shapes your gut microbiome, since fiber changes the availability of certain bacteria in the gut.
There are two very important types of bacteria: Lactobacillus and Bifidobacterium. These bacteria ferment fiber in the gut and produce short-chain fatty acids (SCFAs).
These SCFAs help strengthen your intestinal (gut) barrier.
Having better gut barrier function means you can prevent harmful bacterial products from leaking through into the bloodstream and triggering chronic low-grade inflammation. We know low-grade inflammation in the body is one of the hallmarks of aging in age-related diseases.
If you have fiber-induced changes in the microbiome, these changes improve your metabolic health, enhancing glucose (sugar) and lipid (fat) metabolism and reducing systemic inflammation and oxidative stress. And you produce other metabolites (byproducts of metabolism, like SCFAs) that affect organs like your heart, liver, and brain.
Q: How do you know if you’re getting enough fiber? And does the type of fiber matter?
Imtiaz: The gut microbiome response to fiber is really specific to the amount of fiber you’re consuming and how often you’re eating it. Regular fiber intake helps these bacterial populations produce fatty acids and protect your gut barrier.
You should eat a mix of soluble and insoluble fiber. Soluble fibers dissolve in water and form a gel-like substance that is digested slowly, whereas insoluble fibers don’t dissolve in water and pass through the digestive system more quickly.
Soluble fiber is found in foods like oats, beans, lentils, barley, fruits, vegetables, and flaxseed. You can get insoluble fiber from foods like potato skins, vegetables, brown rice, quinoa, and wheat bran.
A lot of plant foods actually have both types of fiber, so you don’t have to really worry; as long as you’re eating vegetables, you’re good, because you’re getting both types of fiber.
If you’re struggling to get enough fiber, psyllium husk is a really good fiber supplement. (verywellhealth)
