Is there such a thing as too much fiber?

Short answer: Yes. But you might not realize that’s causing your problem.

I came across this amusing/informative article today: 6 Clues You’re Full of Stool and what to do about it. OK, awkward topic. But it may actually be an eye opener for people who have been over-eating fiber in an effort to “fix” their digestive problems, to no avail.

The author, registered dietitian Tamara Freuman, describes the typical scenario for this syndrome. Let’s say you experience chronic bloating and gas, although you’re not officially constipated. You try all the fashionable gut-health diets: gluten-free, FODMAPS, dairy-free. You get tested for all known medical problems. You self-diagnose leaky gut or gut inflammation. You take supplements and herbs.

And you eat loads of fiber. High fiber cereals with nuts and fruit for breakfast. Salads for lunch. Plant-based casseroles for dinner. You snack on high fiber bars, dried fruit and raw veggies. You buy yogurt with added “fiber”. You sprinkle fiber powders into smoothies. And you have a bowel movement every day so you conclude the bloating isn’t constipation. You may add even more fiber to try to fix the problem.

It’s funny to think back to the mid-20th century when many of us were children and remember a time when “fiber” wasn’t even a thing. Our mothers might have said something about roughage, as in you need some roughage in your diet. Celery comes to mind. But fiber was not on the radar screen until sometime in the late 1970’s when nutrition researchers started to associate gastrointestinal disease rates in different cultures with the fiber content of the diet.

In just a year or two, that information translated into a fiber firestorm in developed countries. Wheat bran became the Holy Grail of fiber. You either bought yourself a big bag and sprinkled it on everything, or you bought foods with added wheat bran. Eventually our definition of fiber expanded to include all sorts of food components that were not digestible, from bran to gels to gums, starches and inulin, a carbohydrate that isn’t digested, but that conveniently dissolves into liquids so juices and yogurt can claim to be “high fiber” without the annoyance of chewy bran flakes floating around.

Admittedly many people back then were eating low fiber diets. The most roughage in your day might have been the little pile of over-cooked peas or green beans on your dinner plate. Now some zealous fiber-believers may have the opposite problem: too much fiber.

Why would someone do this? Because the Fiber Health Halo lives on. Fiber and gut health are promoted as the answer to all our problems. When it comes health halo foods and nutrients, plenty of people believe More Is Always Better. The popular emphasis on plant-based diets just reinforces the idea that fiber is universally good and healthful. The problem with fiber in the gut is this: it doesn’t all just move out as quickly as you can eat it. Your intestines take time to process the food you eat; they aren’t on some schedule. The bulkier the food, the more time it takes. The situation can be aggravated if you don’t consume enough fluid to hydrate all that fiber.

What should you do if you recognize your own situation and symptoms in that article? First let me emphasize that not all GI symptoms are caused by excess fiber. If you’ve tried special diets and supplements and you really haven’t experienced remarkable improvement, you may need to consult a gastroenterologist to sort out potential medical problems. If your diet is loaded with fiber, you can always cut back and see how you do.

I’d start with extraneous fiber sources such as: fiber supplements and fiber-fortified foods like energy bars, smoothies, yogurt, bread, candy or cereals. The types of fiber added to these processed foods don’t agree with everyone. You can also cut back on foods like bran cereal, bran-fortified bread or muffins by reducing servings or portion sizes.

In the end, the best source of food fiber is…. real food. Vegetables, fruit, legumes, whole grains, nuts. These foods are filling, so theoretically your stomach will fill up more quickly by eating those foods, making it less likely you can overeat fiber and end up (as Ms. Freuman delicately puts it) F.O.S.