If you’ve ever sat in a doctor’s office and mentioned digestive issues, there’s a good chance you heard three words: eat more fiber.
It’s one of those pieces of advice that’s become so deeply embedded in how we think about nutrition that questioning it feels almost reckless. Fiber is good. Fiber is essential. Without it, your gut will suffer.
I’m not here to tell you fiber is bad—I’m here to suggest that the story is a lot more nuanced than most of us have been told, and that for a meaningful number of people, the path to better gut health might not run through a bowl of bran cereal.
Why Fiber Gets the Credit
The primary reason fiber is considered essential for gut health comes down to one molecule: butyrate.
Butyrate is a short-chain fatty acid, and it’s the primary energy source for colonocytes—the cells that line your colon. From what the research consistently shows, butyrate provides somewhere around 70–80% of the energy these cells need to function. It supports the integrity of the gut lining, plays a role in immune regulation, and helps modulate inflammation. It’s genuinely important stuff.
The logic follows a clean path: fiber feeds gut bacteria, bacteria ferment the fiber and produce butyrate, butyrate nourishes the colon—therefore, fiber is essential.
It’s a tidy narrative. It’s also incomplete.
The Part Nobody Mentions
Here’s where it gets interesting—and where the etymology nerds in the room might already be ahead of me.
The word butyrate comes from butyrum, the Latin word for butter. Butyric acid was first isolated from butter in the early 1800s, and butter remains one of the richest direct dietary sources of it—triglycerides of butyric acid make up roughly 3–4% of butter’s composition. Ghee is another excellent source, along with many full-fat dairy products.
Let that sit for a second: the molecule that fiber gets all the credit for producing is literally named after butter, because butter already has it.
This doesn’t mean fiber fermentation isn’t a valid pathway to butyrate—it is. It means it’s not the only pathway. Your body doesn’t particularly care whether the butyrate arrived via bacterial fermentation of psyllium husk or from a tablespoon of grass-fed butter; butyrate is butyrate.
For anyone eating a ketogenic, carnivore, or low-carb diet who’s been told they’re slowly destroying their gut by not eating enough fiber—this is worth sitting with.
What I’ve Actually Seen in Practice
I work on the patient care team at Revero Health, a metabolic health clinic focused on chronic and autoimmune conditions. We work with patients on elimination diets—primarily carnivore and ketogenic protocols—and we track a wide range of clinical metrics: blood glucose (fasting, pre-meal, and post-meal), blood pressure, ketones, weight, body composition, GI symptoms like gas and bloating, diarrhea, abdominal pain, bowel urgency, mood, energy, sleep quality, and quite a few more.
In my experience serving approximately 300 patients, I’ve watched a pattern repeat itself so consistently that it would be difficult to overlook.
When patients remove fiber—and I mean remove it entirely, not just reduce it—their gut symptoms frequently improve. Sometimes dramatically. Bloating decreases. Bowel regularity improves. Abdominal pain and cramping diminish. For patients with IBS and Crohn’s disease specifically, the improvements have been some of the most striking I’ve observed in my clinical work.
I want to be clear about what I’m saying and what I’m not: I’m not claiming fiber causes gut disease. What I am saying is that for a meaningful number of people—especially those with existing inflammatory or functional GI conditions—removing fiber appears to reduce the burden on an already compromised system. The conventional advice to add more fiber to an irritated gut can sometimes be the equivalent of adding kindling to a fire.
The Butter Connection
This is where it gets personal—and where I’ve seen some of the most fascinating outcomes in my time at Revero.
Approximately 40 of my 300 patients have elected to do extended butter fasts—consuming only butter, salt, and water for a period of typically three days. I want to be transparent: butter fasting is not one of our prescribed protocols at Revero. These patients chose to do this on their own, and we monitored their metrics throughout.
What we observed was interesting, to put it mildly.
Patients who had been dealing with long-standing constipation and bowel irregularities—some for years—reported significant improvement and, in many cases, full resolution of their symptoms during and after butter fasting. Digestive discomfort decreased. Blood sugar regulation improved. These weren’t subtle shifts that required a spreadsheet to detect; patients noticed them and reported them without being prompted.
Even outside the context of fasting, I’ve seen patients with chronic IBS and Crohn’s symptoms find real, sustained relief simply by increasing their butter intake as part of a well-formulated low-carb or carnivore approach. The mechanism makes intuitive sense when you think about it: they’re delivering butyrate directly to the gut without requiring the fermentation step—and without the plant material that may have been contributing to their inflammation in the first place.
Fiber Isn’t the Villain Either
I want to be careful here, because the goal isn’t to create the opposite extreme. Fiber isn’t inherently harmful. For some people, it’s well-tolerated and part of a dietary approach that works for them. I’m not in the business of telling anyone to stop eating vegetables if vegetables make them feel good.
What I am pushing back on is the idea that fiber is universally essential—that without it, your gut will inevitably suffer. That narrative doesn’t hold up against what I’ve observed clinically, and it certainly doesn’t hold up once you realize that the molecule fiber is credited with producing is available directly from dietary sources that don’t require bacterial fermentation at all.
People on well-formulated carnivore diets—eating zero fiber—maintain healthy bowel function, robust gut lining integrity, and excellent metabolic markers. I see it every day. We track the data. “Common” dietary advice doesn’t always equate to what’s actually necessary, and just because the majority of guidelines center fiber doesn’t mean its absence is pathological.
What Does This Mean for You?
If you’re someone who’s been eating low-carb, keto, or carnivore and feeling great—but carrying a quiet guilt about not eating enough fiber—I hope this gives you some peace of mind. Your body has other ways of getting what it needs, and the butyrate your colon relies on doesn’t have to come from a fiber supplement.
If you’re dealing with chronic gut issues and you’ve tried adding more fiber on your doctor’s recommendation without success, it might be worth exploring whether reducing or removing fiber—while incorporating more butter and animal fats—changes anything for you. This is the kind of conversation worth having with a practitioner who understands these protocols and can walk alongside you through the process.
I don’t have all the answers; I never will. I’m one coach with one clinical lens, sharing what I’ve observed across hundreds of patient interactions. Time will tell whether the broader clinical picture catches up to what many of us in this space are already seeing.
I hope my observations give someone some hope and direction.
Rance Edwards is a National Board Certified Health and Wellness Coach (NBC-HWC) with over 2,000 clinical hours of experience, specializing in chronic disease management and lifestyle medicine.
If you’re navigating gut health challenges and wondering whether a dietary approach might help, I’d love to have that conversation with you—no pressure, no sales pitch. Just a real conversation about what might work for your situation. Let’s have a conversation →