Is Fibermaxxing the Next Big Thing in Nutrition, or Just Another Trend?

There’s no shortage of online wellness movements that promise to improve your health. But a new one has recently popped up that focuses on your gut. It’s called “fibermaxxing.” And the idea is simple: Eat more fiber to improve your digestion, boost your metabolism and immune system, and reduce your risk of disease.

On TikTok and Instagram, the fibermaxxing trend typically shows up in the form of towering lentil salads, chia-seed puddings, and smoothies packed with leafy greens and flaxseed. But does the science behind fibermaxxing actually support the hype?

According to Dr. Urvi Shah, a board-certified hematologist-oncologist and physician at Memorial Sloan Kettering Cancer Center, at its core, fibermaxxing seems to be largely based on solid science. Shah is currently leading several research studies focused on the health effects of high-fiber plant-based diets, especially in patients at risk for cancers like multiple myeloma.

What Is Fibermaxxing?

Fibermaxxing is the practice of drastically increasing your dietary fiber intake, sometimes beyond the daily recommended amount of 25 to 30 grams. The ultimate goal is to improve your gut health, metabolism, and overall physical health. But while the term fibermaxxing might sound a bit buzzy, it’s rooted in decades of nutritional research.

Diets higher in fiber are consistently linked to a slew of health benefits, including lower risks of heart disease, diabetes, and colorectal cancer, as well as better weight control and digestive health. That’s why Shah says the fibermaxxing trend gets several things right.

For instance, eating a wide variety of plant-based high-fiber foods — which is one of the tenets of fibermaxxing — is important, she says. “Different fiber types feed different microbes,” so eating a diverse range of plant foods is beneficial. Furthermore, the fibermaxxing focus on eating whole foods is better than consuming isolated fiber, such as fiber-enriched foods or fiber supplements.

“Whole plants give fiber, polyphenols, and micronutrients that synergize with the microbiome,” she says. And “prebiotic-rich foods can reshape microbiota and increase beneficial taxa and SCFAs [short-chain fatty acids]” like butyrate, which has “anti-inflammatory and anti-cancer properties,” Shah adds.

In other words, increasing fiber through whole, minimally processed plant foods, rather than relying on powders or pills, really does have a meaningful impact on gut health.

A Clinical Look at Fiber’s Impact

Shah previously led a nutrition prevention study (NUTRIVENTION), which tested whether plant-based, high-fiber diets could benefit patients with precursor conditions to multiple myeloma. These patients were not yet sick, but they faced a higher risk of developing the serious cancer.

“Our pilot study provided a high-fiber, plant-based diet to patients at risk for developing multiple myeloma, a blood cancer that develops in bone marrow plasma cells,” Shah says. “Patients were given 12 weeks of high-fiber, plant-based meals from Plantable, 24 weeks of nutritional counseling, and were followed for 52 weeks.”

Shah says the results showed the fiber-rich diet approach was “well-received by patients,” who largely stuck with the diet and lost weight. And perhaps more importantly, the participants experienced improvements in overall diet quality, quality of life, gut microbiome diversity, and immune function.

“This study demonstrates the potential role that modifiable risk factors, such as diet, can have on patients at risk for developing multiple myeloma and other cancers,” Shah says.

What Fibermaxxing Gets Right, And Wrong

While there is strong evidence supporting higher fiber intake, Shah cautions that the fibermaxxing trend can oversimplify some complex science.

For example, people who jump into very high fiber intake too quickly may experience bloating or digestive discomfort.

“Sudden very high doses can produce bloating or gas, and tolerability varies,” Shah says. “[T]he microbiome needs to adapt.”

She also emphasizes that fiber supplements are not a perfect substitute for food-based sources.

“Many advocates treat isolated prebiotics as equivalent to a plant-rich diet,” she says. However, “evidence shows supplements often change a narrow subset of microbes, and effects can be transient.”

That said, the benefits of increasing fiber, especially from a variety of plant-based sources, are very real. According to Shah, the most well-supported outcomes include:

Improved bowel regularity and constipation relief
Lower LDL cholesterol and reduced cardiovascular risk
Improved blood sugar management and lower risk of type 2 diabetes
Support for weight management and satiety
Enhanced gut metabolites like butyrate, which may benefit colon health and help regulate inflammation
Reduced risk of some cancers, including colorectal cancer

However, Shah warns against broad claims that fiber can prevent all cancers. While higher fiber intake is associated with lower cancer risk, the effect varies depending on cancer type and other factors.

4 Ways to Increase Fiber the Right Way

For those looking to try fibermaxxing, Shah offers several practical tips based on her research:

Aim for at least 30 grams of fiber per day. “Beans and lentils are a top source of fiber,” Shah says, “and 1 cup will give you 15 grams of fiber, which is half the daily requirement, and 15 grams of protein too!”
Eat a wide variety of plants to nourish a diverse microbiome. “Consider a variety of plant foods. That is, at least 30 different plant foods per week,” Shah says. “Go out of your comfort zone in picking plant foods if you can!”
Add fermented foods. “Fermented foods like sauerkraut and kimchi are great for gut health,” Shah says. So try adding a few small servings with your meals several times a day.
Blend it up. If you struggle to eat enough plant-based food each day, Shah says, “then consider a high-fiber smoothie that blends berries/fruit, green leafy veggies, chia/flax/hemp seeds, and silken tofu for a protein source.”

Shah also points out that constipation, hard stools, bloating, and infrequent bowel movements are common signs that you may not be getting enough fiber. These symptoms often signal a diet lacking in whole plant foods.

A Smarter Way to Think About Fiber

Fibermaxxing is admittedly a pretty flashy name. But it’s largely grounded in real science. The key is to focus on increasing fiber intake by consistently and sufficiently eating whole, plant-based foods rather than relying on supplements or making sudden, drastic changes.

In short, adding more fiber to your diet may not solve everything overnight. But it can be a simple, effective step toward better health.

This article is not offering medical advice and should be used for informational purposes only.

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