October 2025
DOCTORS WARN AGAINST TOO MUCH FIBER-ENRICHED FOODS
Fiber-enriched products are hot. Manufacturers are packing fiber into everything from soda and energy drinks to doughnuts and snack bars. “Fibermaxxing,” where people post their efforts to load up on fiber, is trending on social media. But emerging research shows that some fibers used in these products, especially in high doses, could lead to serious health problems. And a growing number of physicians and nutrition experts say you should skip them. People are overdoing it thinking more is better, but too much of a good thing is too much of a good thing. Fiber usually leads to reduced inflammation, but in some people, fiber can cause inflammation. Dietitians are hearing patients complain of bloating, gas, and pain after consuming these fiber-enriched, packaged foods and drinks.
There is a big difference between eating naturally high-fiber foods like vegetables, fruits, beans, whole grains, nuts and seeds, and fiber-enhanced processed foods and supplements. Fiber is generally good for us. And most people don’t consume enough dietary fiber, which is that part of plant foods our bodies generally can’t digest. Fiber keeps us full, lowers cholesterol, and helps stabilize blood sugar. People who eat high-fiber diets have lower risks of obesity, heart disease, cancer, and type-2 diabetes. Eating a variety of fiber-rich foods means getting a range of different fibers. This is important for the healthy functioning of the gut microbiome, the collection of microbes that inhabit our digestive tract. Individual fibers feed different healthy bacteria, and newer research is finding that the various types of fibers have specific, and different, mechanisms affecting health. You can’t eat junk all day and then have a fiber-rich soda and think you’ve met the day’s fiber quota.
Many snack bars and drinks with added fiber aren’t things we should be eating anyway. They often contain high amounts of added sweeteners and include additives such as emulsifiers, which studies have found cause dysfunction in the microbiome. The added fiber, which is often touted on the label, gives these products a “health halo,” making them more appealing to consumers. One of the main fibers used in packaged foods and drinks is inulin, which is usually derived from chicory root. In high doses, inulin has been shown to alter the immune system in a way that may increase the risk of liver cancer. High doses of inulin can also alter liver enzymes. While scientists note that studies are small, the results are of concern.
The benefits of naturally occurring fiber are difficult, if not impossible, to safely reproduce by using packaged foods and engineered products. Many fiber-enriched packaged foods contain only one or two types of fiber. Consuming large amounts of some specific fibers could lead to excessive growth of the specific bacteria in the gut that feed on those fibers, throwing off the microbiome’s balance. You don’t want one or two microbes that completely overwhelm the digestive system. Eating large amounts of processed fibers can trigger inflammation and cause symptoms like pain and bloating. These processed fiber foods can also exacerbate symptoms of multiple sclerosis and GI disorders like inflammatory bowel disease. The issue is that the digestive system can’t adequately break down this processed fiber.
Dietitians and physicians say the takeaway is to get your fiber from whole, unprocessed foods. Just eating an apple is probably the best fiber supplement you can imagine. Add foods rich in the other types of fiber for optimal digestive health. Talk with your physician or registered dietitian about the amount per day and the types best for you.
Andrea Petersen