What is ‘fibermaxxing?’ Dietitian warns about pitfalls of viral health trend — and the change to keep an eye on

Talk about a bowel movement. 

From chia-studded puddings to lentil-loaded lunches, wellness influencers are flooding social media with high-fiber feasts they say improve digestion and ward off weight gain. 

But can too much fiber backfire? Maura Donovan, a registered dietician and medical education specialist of sports nutrition at Thorne, has the low-down on “fiber maxxing” — and how to know if you’ve gone too far. 

What is fibermaxxing?

It’s a viral trend in which people are packing their plates with fiber-rich foods — like whole grains, legumes, fruits, vegetables, nuts and seeds — to maximize their daily intake. Many are also turning to supplements for an extra boost.

“Similar to the benefits of eating a high-protein diet, many are over-indulging in fiber for weight and diet management, as well as reducing inflammation in the body, which can help us look and feel better from the inside-out,” Donovan said. 

The benefits of boosting fiber

Fiber offers some major perks — especially for your gut health.

“When fiber reaches the large intestine in the digestive tract, it is fermented by gut microbiota and can produce beneficial byproducts such as short-chain fatty acids and other metabolites,” Donovan explained. 

These byproducts act as energy sources for the cells lining the large intestine, strengthen the gut barrier and reduce inflammation in the gastrointestinal (GI) tract. 

A high-fiber diet supports smooth, regular bowel movements and lowers the risk of constipation, hemorrhoids, diverticular disease and even colon cancer.

Fiber-rich foods also tend to fill you up and digest slowly, helping you stay satisfied longer and cut back on overall calorie intake. 

On top of that, research suggests that a higher fiber intake can lower cholesterol, blood sugar and blood pressure levels, keeping your heart healthy and possibly adding extra years to your life. 

The negative side effects of fibermaxxing

Before you start sprinkling flaxseed into everything, just know: More fiber isn’t always better.

“Fiber is a nutrient that helps you feel full and stay full for longer, so if fiber is causing you to eat less, you may not be getting enough nutrients to support your body daily,” Donovan warned. 

Our bodies also can’t break down fiber, so it passes through our digestive systems mostly intact. 

“If someone who is typically eating 10 grams of fiber per day suddenly maximizes their fiber intake, they will most likely experience uncomfortable GI symptoms like gas, bloating and cramping,” Donovan said. 

She also noted that too much fiber can interfere with the body’s ability to absorb key nutrients like iron, calcium, and zinc — raising the risk of deficiencies.

So how much fiber should you consume?

The Dietary Guidelines for Americans recommends about 25 grams of fiber per day for women and 38 grams for men, though that number drops slightly if you’re ever 50. 

Despite the benefits of fiber, the federal government estimates that more than 90% of women and 97% of men fall short of the daily targets.

“Those recommended daily allowances are a great amount to aim for, in the right context for a healthy individual,” Donovn said.

“However, it is important to start where you are and work up to those recommendations from there, to avoid any GI discomfort.”

How to scale up safely 

When boosting fiber in your diet, Donovan warned against adding so much that you’re too full to eat other important foods or struggling to digest them. 

“With increased fiber intake, you may notice some changes in bowel patterns (hopefully, positive ones!), but keep an eye on these to make sure they’re not changing drastically from what you’re used to,” she said. “This could be an indication you’re overdoing it on the fiber.”

Donovan also stressed that fibermaxxing isn’t about quick fixes or crash dieting. Instead, it’s important to adopt a sustainable approach you can maintain long-term to reap the most benefits.

“If you consume too much fiber too soon on your fibermaxxing journey, the side effects and discomfort might deter you from this healthy habit,” she said.