Is Fibermaxxing Worth It?
Fiber is having a moment. Is "fibermaxxing" too much of a good thing?
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One of our patients is in treatment for OCD and orthorexia — the preoccupation with “clean” or “healthy” eating that can quietly become its own kind of disorder. She’s doing the hard work of nutritionally restoring. But she’s also eating so much fiber at every meal that she can’t physically fit in enough calories to heal.
She’s not doing this because she saw a trending video. She’s doing it because fiber has quietly become one of the “safe” foods in a mind that’s still learning to trust food again. But it’s a window into something we’re seeing more broadly right now.
Around the same time, another patient texted one of us in a panic. She’d seen a headline about fiber and perimenopause, decided on the spot to hit 35 grams the next day, and ended up doubling her intake overnight. She felt terrible within hours.
Fiber is officially having a moment. It has a name now — “fibermaxxing” — and it’s everywhere. So let’s slow down and ask: is more fiber always better? And is fibermaxxing actually doing what it promises?
The Claim
“Fibermaxxing” is the trend of dramatically increasing fiber intake, often well beyond standard recommendations, by adding fiber to nearly everything. Common claims circulating online include that more fiber automatically means better gut health, that fiber keeps you full and helps with weight loss, and that because most people are fiber deficient, you basically can’t overdo it. The trend has spawned a whole category of products — fiber sodas, fiber powders you stir into your drink, gummies, and “sugar into fiber” supplements — all promising an easy fix.
Why It’s Going Viral
Fiber may be the last macronutrient we hadn’t yet turned into an extreme. Low carb, low fat, keto, carnivore — we’ve cycled through the diet wars, and fibermaxxing is, in some ways, the next iteration: taking something genuinely healthy and pushing it to a disordered extreme, then giving it a catchy name.
There’s also a real business opportunity here. It’s easy to sell a fix for a problem people already sense they have. Add a magic powder that turns sugar into fiber to your cart. Grab a fiber soda instead of your usual can. Influencers are being sent these products to promote, which increases their visibility in everyone’s feed.
And underneath the trend is a kernel of legitimate concern: there’s increased cultural awareness right now around ultra-processed foods and a broader “eat real food” movement. That awareness is, in many ways, warranted — American diets have shifted toward low-fiber, highly processed foods, and most of us are probably eating historically low amounts of fiber. The desire to fix that isn’t irrational. It’s the solution — buy a product — that deserves scrutiny.
What the Science Shows
Let’s start with what’s true: fiber matters, and most people aren’t getting enough. The Academy of Nutrition and Dietetics’ position statement on dietary fiber notes that populations who eat more fiber have lower rates of chronic disease, including cardiovascular disease, type 2 diabetes, and some cancers. Adequate intake is about 25 grams a day for women and 38 grams for men. The average American gets about 17 grams a day, and only about 5% of the population meets the recommended intake. That’s a real gap, and it has real health implications.
But “more fiber” isn’t one thing. There are three broad categories, and they don’t do the same job in your body.
Insoluble fiber (whole grains, leafy greens, skins of fruits and vegetables, nuts and seeds) primarily helps with bowel regularity. Larger, coarser particles mechanically stimulate the lining of the large intestine to release water and mucus, keeping stool moving. Notably, if it’s ground too fine, it can lose that effect — and can even be constipating.
Soluble, gel-forming fiber (oats, legumes, the flesh of fruits, and supplements like psyllium, guar gum, and beta-glucan) forms a viscous gel in the gut. That gel is what traps and eliminates cholesterol-carrying bile, and it’s what slows and blunts the absorption of glucose after a meal — meaningfully lowering cholesterol and improving post-meal blood sugar. This is the fiber doing the things people usually associate with “fiber is good for you.” Critically, processing matters: one study found that beta-glucan’s cholesterol-lowering effect held up in a drink but was blunted when baked into bread and cookies — the same fiber, different structure, different result.
Prebiotic, fermentable fiber (inulin and similar fructans, found naturally in chicory root, Jerusalem artichokes, garlic, and onions — and added to most of the trendy fiber products) gets broken down by gut bacteria rather than passing through intact. That means it can feed healthy bacteria, but it doesn’t form the gel needed to lower cholesterol or blunt glucose, and a review of 14 randomized controlled trials found no improvement in glycemic control from these fibers versus placebo, and no effect on stool output or softening. What it reliably does produce is gas.
This distinction matters commercially, too. Most viral fiber sodas and gummies are built on inulin or similar prebiotic fibers — not the gel-forming kind. Class-action lawsuits filed against two popular fiber soda brands allege that the actual prebiotic content per can is too low to produce a meaningful gut-health benefit, and that a person would need to drink several cans a day to approach a clinically relevant dose — at which point the added sugar likely offsets any benefit anyway.
There is a real, evidence-based way to supplement fiber when food alone isn’t enough: gel-forming soluble fiber, like psyllium, taken consistently. It’s inexpensive, well studied, and effective for both bowel regularity and metabolic markers. A broader meta-analysis of fiber-fortified foods found consistent improvements in body weight, cholesterol, triglycerides, fasting glucose, and HbA1c — with better results from solid or semi-solid foods than from liquids, and no added benefit from going above roughly 15 grams a day of fortification.
Clinical Nuance
None of this means fiber is dangerous, or that anyone who’s tried a fiber soda made a mistake. It means the marketing is outrunning the biology. The type of fiber, its source, and how it’s been processed all determine whether it actually does what’s being promised — and “high fiber” on a label doesn’t guarantee any of that.
There’s also a real, if less discussed, downside to fibermaxxing itself. Increasing fiber too quickly, without adequate water, causes real GI distress — bloating, gas, and discomfort that can be significant. Fermentable, prebiotic fibers in particular can produce a lot of gas as they’re broken down.
More importantly, fiber-heavy foods are typically lower in calorie density and take up real volume in the stomach. For patients with disordered eating patterns, especially orthorexia, that property can become a way to fill up without taking in adequate calories, protein, or fat, crowding out the nutrition they actually need. This is a genuine clinical concern, not a hypothetical one.
And there’s a financial dimension worth naming honestly: fibermaxxing products are often expensive, and the marketing implies they’re solving a problem that, for most people, food can solve more effectively and more cheaply. Dollars spent on specialty fiber sodas are dollars not spent on the produce, whole grains, and legumes that would do more for the same person’s health.
The most useful frame here: fiber deserves attention, food is the best source, and increases should be gradual, paired with adequate water, and thought of as one piece of an overall pattern — not a hack, and not a race to a number.
The Antidote
For Patients
Wanting to eat healthier is not the same thing as needing to maximize every nutrient.
More fiber is not automatically better fiber — the type and source matter.
If a fiber product made me feel worse instead of better, that’s useful information, not a personal failure.
I can increase fiber slowly, with plenty of water, and give my body time to adjust.
Food can meet my fiber needs. I don’t need an expensive product to be doing this “right.”
If eating enough fiber ever makes it harder to eat enough food overall, that’s worth talking to my doctor about — not pushing through.
For Clinicians
“Fiber really does matter, and most people aren’t getting enough — let’s talk about where it’s actually helpful.”
“Not all fiber does the same job. The gel-forming kind, like psyllium, is the one with the strongest evidence for cholesterol and blood sugar.”
“If a product markets itself as high fiber, it’s worth checking whether that fiber is coming from inulin — that changes what it can and can’t do for you.”
“Let’s increase this gradually and make sure you’re drinking enough water, so your gut has time to adjust.”
“The cheapest plain psyllium powder works as well as — or better than — the trendy version.”
“If getting enough fiber is making it harder to get enough calories or variety in your diet, I want to know about that.”
Sources and Further Reading
Dahl WJ, Stewart ML. Position of the Academy of Nutrition and Dietetics: Health Implications of Dietary Fiber. J Acad Nutr Diet. 2015.
McRorie J, McKeown N. Understanding the Physics of Functional Fibers in the Gastrointestinal Tract: An Evidence-Based Approach to Resolving Enduring Misconceptions about Insoluble and Soluble Fiber. J Acad Nutr Diet. 2016.
Kerckhoffs DA, Hornstra G, Mensink RP. Cholesterol-lowering effect of beta-glucan from oat bran in mildly hypercholesterolemic subjects may decrease when beta-glucan is incorporated into bread and cookies. Am J Clin Nutr. 2003.
Lee DPS, Peng A, Taniasuri F, Tan D, Kim JE. Impact of fiber-fortified food consumption on anthropometric measurements and cardiometabolic outcomes: a systematic review, meta-analyses, and meta-regressions of randomized controlled trials. Crit Rev Food Sci Nutr. 2023.
Top Class Actions. Poppi “Gut Healthy” Soda Class Action Settlement. topclassactions.com
Somers v. Olipop, Inc. Complaint. classaction.org, 2025.