5 Telltale Signs You've Had Too Much Fiber + What To Do About It

Dietary fiber is essential for maintaining good digestion, regular bowel movements, and satiety (i.e., feeling full), and yet, 95% of Americans1 don't get enough fiber in their diets. If you're someone who isn't meeting their daily dietary fiber needs (and statistically speaking, you probably are), you may be wondering how much you need to add to your diet—and how much fiber is too much.

Yes, it's possible to have too much fiber. However, the exact amount that qualifies as "too much" varies from person to person. 

The National Academies2 recommends that women under 50 have at least 25 to 28 grams of fiber per day, while men under 50 should strive for at least 38 grams daily. The intake recommendations also decrease slightly for individuals 51 and up.

The National Academies hasn't established an upper tolerable limit for this essential nutrient (i.e., we must consume it daily because our bodies cannot synthesize fiber), as the consequences of having "too much" fiber are individualized and varied. In terms of safety, there isn't evidence that suggests a certain amount results in serious side effects.

There are a few signs that can clue you in that you might have had too much fiber (especially in a short period of time and if you haven't routinely consumed much fiber before). 

"When you have too much fiber, it can sometimes contribute to digestive upset," says Jessica Cording, M.S., R.D., CDN, a registered dietitian, health coach, and author of The Little Book of Game Changers. It's important to have enough fiber to have regular bowel movements, but too much fiber can make some people feel backed up, she says. 

The opposite can also happen: "For some individuals, too much fiber will cause loose stools," Gans says.

And while you may experience less-than-desirable effects of increased fiber if you up your daily intake drastically (it's better to ease into fiber additions), it's worth noting that most Americans are far more likely to miss the mark on their recommended dosage. In fact, a 2017 scientific review published in the American Journal of Lifestyle Medicine3 found that the average American only eats about 16 grams of fiber a day—less than the recommended amount for a 1- to 3-year-old. 

In general, Cording says it's very rare that she recommends people have more than 40 grams of fiber a day. Still, some people may be able to tolerate 50 grams of fiber without any issues, Gans says—but beyond that is really pushing it. For example, "100 grams per day is definitely a lot of fiber, and I would guess that, for the majority of people, it would be too much for their bodies to digest on a daily basis," Gans explains. 

If you're concerned you're not getting enough fiber in your diet, Cording suggests "making it a point to incorporate one high-fiber food into each meal." That includes wonderfully colorful plants like leafy greens (spinach, Swiss chard, collard greens), cruciferous vegetables (kale, broccoli, Brussels sprouts, cauliflower), carrots, raspberries, apples, pears, whole grains, beans, lentils, or avocados. 

"If you find it hard to meet your needs through food (maybe those are foods that you don't really like that much, or they don't fit into your day-to-day routine), fiber supplements can be useful," Cording says. "Supplements can also be useful if you find your needs have increased for whatever reason—like you're dealing with irregularity that's backing you up." 

If you have too much fiber, Gans says you shouldn't panic. However, you might have some unwanted gastrointestinal side effects, like gas and bloating. "If you are experiencing negative side effects, try drinking plenty of water and eating bland foods—such as white rice, chicken, eggs, and white toast—until you feel better," she says. 

Research—including a 2020 narrative review of meta-analyses from the Journal of Chiropractic Medicine—has found that fiber supplementation is important to support regular bowel movements, along with gut motility.* 

Fiber helps support the immune system, primarily in the gut, but that benefits the entire body. According to a 2021 review, fiber helps promote the function of short-chain fatty acids as it ferments in the gut, strengthening the gut barrier6 in the process.*

Fiber is an important part of a healthy diet, but it is possible to overdo it. That said, the vast majority of people are failing to meet their recommended daily dose of fiber, so it's far more likely your daily intake is missing the mark.