Fibermaxxing for Dogs: What the Trend Gets Right About Canine Nutrition

If you have been anywhere near nutrition content lately, you have probably encountered the word "fibermaxxing." It is fiber's long overdue moment in the spotlight — and for once, the nutrition internet is not completely wrong.

While protein has dominated the wellness conversation for years — with protein bars, protein coffee, protein pasta — a quieter counter-trend has been gaining ground. People are starting to ask a different question: not "am I getting enough protein?" but "am I getting enough fiber?" The answers, it turns out, are basically opposite. Most of us are getting too much of one and not nearly enough of the other. And the same is probably true for your dog.

What Is Fibermaxxing?

"Fibermaxxing" is exactly what it sounds like: deliberately prioritizing and maximizing fiber intake, typically by eating more whole foods like legumes, vegetables, whole grains, fruits, nuts, and seeds.¹ The trend took hold on TikTok and other social media platforms in 2024 and 2025, where creators began showcasing high-fiber meals and challenging each other to eat 30+ different plants per week. Unlike many trends that arrive with red flags attached, this one has drawn an unusually enthusiastic response from registered dietitians and physicians.^2,3

Mayo Clinic dietitian Tara Schmidt put it plainly: "Looking at all the TikTok trends that are related to food out there, I'm OK with fibermaxxing."⁴

The Problem With the Protein Obsession (For Humans, and Their Dogs)

Protein has had an extraordinary run as the wellness world's favorite macronutrient. And protein is genuinely important — it supports muscle maintenance, satiety, and cellular repair. The issue isn't protein itself. The issue is where most of that protein comes from.

For most Americans, high-protein diets mean diets high in red and processed meat. That combination carries well-documented risks. A landmark Harvard study prospectively tracking over 120,000 adults found that high consumption of processed meat is associated with increased risk of heart disease, colorectal cancer, type 2 diabetes, and all-cause mortality.⁵ The International Agency for Research on Cancer classifies processed meats — bacon, hot dogs, deli meats — as Group 1 carcinogens, meaning there is sufficient evidence they cause cancer.⁶ Red meat is classified as Group 2A, "probably carcinogenic."

And crucially, there is no protein deficiency epidemic driving any of this. Most Americans already meet or exceed their protein requirements.⁷ What the data consistently shows is a deficiency in something else entirely.

Fiber has been officially classified by the Dietary Guidelines for Americans as a "nutrient of public health concern" — meaning chronic underconsumption poses a meaningful population-level health risk.⁸ And yet, for decades, it barely registered in the public nutrition conversation. Fibermaxxing, whatever its social media packaging, is essentially a corrective to a very real and very longstanding nutritional gap.

Why Fiber Has No Real Downside

One of the reasons dietitians are comfortable endorsing fibermaxxing is that fiber — unlike protein from animal sources, fat, or added sugar — does not come with a list of associated health risks when consumed from whole foods. The main practical caution is transitional: increasing fiber intake too quickly can cause temporary gas or bloating as gut bacteria adapt.² The fix is simple: go gradually and drink more water. There is no upper limit on fiber from food that is associated with harm.

This is a genuinely unusual position for a nutrient to be in. Most dietary recommendations involve balance, moderation, and risk trade-offs. Fiber is mostly just: more is better, within reason, and the average person has significant room to get there.

Now, About Your Dog

Pet nutrition trends have always followed human nutrition trends closely, and the relationship is not coincidental — dogs are omnivores whose gut physiology shares meaningful similarities with ours.⁹ Research has directly compared the dog and human gut microbiomes and found substantial overlap in gene content and dietary response.¹⁰ The fiber story that is playing out in human nutrition has a direct parallel in canine nutrition.

Most conventional dog foods are formulated to meet minimum nutritional requirements, with crude fiber listed as a small fraction of the guaranteed analysis — often 3–5% or less. The emphasis has historically been on protein and fat. Fiber, like in the human food supply, has been undervalued. The average meat-based kibble delivers roughly 10–13g of dietary fiber per cup; plant-based formulas built around legumes and whole grains can deliver 50% more — through the ingredients themselves, not added supplements.

But the canine research is catching up. And what it's showing looks a lot like the human picture.

The Gut Microbiome Connection

One of the most compelling bodies of evidence linking fiber to long-term canine health runs through the gut microbiome — the vast community of bacteria, fungi, and other microorganisms that inhabit your dog's digestive tract and influence everything from immune function to mood to chronic disease risk.

A 2024 study published in mSystems — co-authored by researchers at the Waltham Petcare Science Institute — analyzed fecal microbiome and metabolome data from dogs fed 12 different test diets varying in fiber sources and quantities.¹¹ The findings were striking: dietary fiber was the single strongest driver of changes in gut microbial metabolites, including short-chain fatty acids (SCFAs) — compounds like butyrate, acetate, and propionate that are central to gut and metabolic health. Higher fiber diets enriched 14 distinct microbial species associated with beneficial fermentation, and the production of health-relevant metabolites was more pronounced in response to fiber-containing diets than to any other dietary variable studied.

Separately, Dr. Sarah Dodd and colleagues at the University of Guelph's Ontario Veterinary College have examined the canine microbiome and metabolome in response to plant-based versus animal-based diets.¹³ Plant-based diets, which are inherently higher in fiber, were associated with changes in microbial community composition consistent with the patterns seen in healthy dogs with good digestive function. A parallel metabolomics study found distinct fecal metabolomic signatures associated with plant-based dietary patterns, reflecting the downstream products of fiber fermentation — the same metabolite shifts associated with gut health outcomes in human nutrition research.¹⁴

In the Dodd et al. 2022 owner-reported health survey of 1,189 dog guardians — including 357 feeding entirely plant-based diets — dogs on plant-forward diets were reported as more likely to enjoy very good health, and less likely to suffer gastrointestinal and hepatic (liver) disorders compared to those on conventional diets.¹⁵ While owner-reported data carries limitations, the direction and scale of these findings is consistent with the mechanistic microbiome research.

Fiber, Satiety, and the Canine Obesity Crisis

Between 34% and 59% of dogs in the United States and Europe are currently overweight or obese — a scale that mirrors the human obesity epidemic and carries similar downstream health risks, from joint disease to diabetes to reduced lifespan.¹⁶

Fiber helps here through multiple mechanisms, and the research is clearer than you might expect.

A study published in the British Journal of Nutrition directly tested this in dogs: animals fed a higher fermentable fiber diet had significantly greater SCFA production and voluntarily consumed less food when subsequently offered a challenge meal, compared to dogs on a lower fiber diet.¹⁷ A separate study of high-protein, high-fiber weight loss diets found similar effects — the combination reliably improved short-term satiety compared to protein or fiber alone.¹⁸

The practical implication: a dog that feels more satisfied from a smaller number of calories is less likely to beg, less likely to overeat, and easier to maintain at a healthy body weight — without requiring you to drastically cut their food volume.

Plant Proteins: The Fiber Bonus

One reason the fibermaxxing conversation is particularly relevant to Petaluma pet parents is that plant proteins — peas, lentils, chickpeas, soy — are high-quality protein sources that, when properly formulated, meet dogs' complete essential amino acid requirements. They also come packaged with fiber. This is the fundamental nutritional difference between plant-based and animal-based protein sources: when you add plant protein to a diet, you get fiber as part of the deal. When you add animal protein, you don't.

Conventional dog foods built primarily on chicken meal, beef, or pork byproducts deliver protein and fat. They deliver very little fermentable fiber — the type that feeds beneficial gut bacteria and produces SCFAs. The microbiome research is clear on this: dogs fed higher-meat, lower-fiber diets show decreased populations of Firmicutes species — particularly fiber-fermenting genera like Faecalibacterium — along with corresponding reductions in the short-chain fatty acids that support gut lining integrity, immune function, and metabolic health.¹⁹

This Isn't a Trend. It's Just Good Nutrition.

Fibermaxxing is a useful cultural hook — it's gotten a genuinely important nutritional message in front of millions of people who weren't thinking about fiber. But it's worth being clear: the underlying science is not new, and it's not trend-dependent. The relationship between dietary fiber, gut microbiome health, satiety, weight management, and reduced chronic disease risk has been accumulating in peer-reviewed literature for decades. In canine nutrition, the same story has been building — it has just had fewer TikTok creators to amplify it.

What the fibermaxxing conversation is really asking, for both you and your dog, is whether your diet is built primarily around whole plant foods or primarily around processed animal products. That question has a clear evidence-based answer.

Frequently Asked Questions

How do I know how much fiber is in my dog's food?

This is harder than it should be. AAFCO — the body that sets nutritional standards for pet food — does not currently require dog food labels to list dietary fiber content. Most guaranteed analyses only show crude fiber, which is a poor proxy for total dietary fiber and does not distinguish between fermentable and non-fermentable types. AAFCO has indicated it will begin requiring brands to publish dietary fiber information in a format similar to human nutrition labels, but that requirement is not yet in effect.

In the meantime, there is no AAFCO-defined minimum or maximum for dietary fiber — the amount is left entirely to each brand or formulator's discretion. If your current dog food doesn't list dietary fiber, you can ask the manufacturer to share that data from their own lab testing. Petaluma includes dietary fiber in its full nutritional analyses, available on each product page.

Can dogs eat too much fiber?

In practical terms, the risk of dogs getting too much fiber from a well-formulated complete diet is low. Very high levels of fiber can reduce the digestibility of other nutrients, which is why balance and formulation quality matter. The concern for most dogs is the opposite problem: not enough fermentable fiber to support a healthy gut microbiome. Consult your veterinarian before making major dietary changes, especially for dogs with existing gastrointestinal conditions.

Aren't dogs carnivores? Do they really need fiber?

Dogs are omnivores, not carnivores — and the distinction matters. Unlike cats, who are obligate carnivores, dogs evolved alongside humans over thousands of years consuming a varied diet that included plant material, cooked starches, and fermentable fibers. One of the clearest genetic markers of this is that dogs have significantly more copies of the amylase gene than wolves, a direct adaptation for digesting starch. Their gut microbiome reflects this too: dogs maintain meaningful populations of fiber-fermenting bacteria, and research consistently shows those populations respond positively to higher fiber intake — producing the short-chain fatty acids that support gut health, immune function, and metabolic regulation.

What are the best fiber sources for dogs?

Fermentable fiber sources — those that feed gut bacteria and produce SCFAs — are particularly valuable. These include legumes (peas, lentils, chickpeas), beet pulp, oats, and inulin-containing ingredients. Insoluble fiber from vegetables, whole grains, and plant hulls also contributes to gut motility and stool quality. The best approach is variety across fiber types, delivered through a well-formulated complete diet rather than added as isolated supplements.

Is fibermaxxing safe for puppies and senior dogs?

Fiber requirements and tolerance vary across life stages, and formulation matters significantly. Puppy foods, senior diets, and weight management formulas are designed with different fiber profiles. This is one reason why a nutritionally complete, life-stage-appropriate diet is important — it takes these variables into account rather than leaving fiber intake to chance.

What about dogs with sensitive stomachs?

Dogs transitioning to a higher-fiber diet may experience temporary loose stools or gas as their gut bacteria adapt — the same adjustment period humans experience. A gradual transition over 7–10 days is recommended. Dogs with existing gastrointestinal conditions should be managed in consultation with a veterinarian, as some conditions may require specific fiber types or adjusted levels.

This post is for informational purposes only and does not constitute veterinary medical advice. Always consult your veterinarian regarding your dog's specific health and dietary needs.

References

1. CNBC. "Food brands chase fibermaxxing trend with new high-fiber products." December 12, 2025. cnbc.com
2. Ochsner Health. "What is Fibermaxxing? 4 Tips for Easing Into This Nutrition Trend." October 22, 2025. ochsner.org
3. U.S. News. "Fibermaxxing: A Dietitian Explains the Latest Nutrition Trend." August 22, 2025. health.usnews.com
4. Mayo Clinic Press. "Fibermaxxing: Is this TikTok trend good for you?" 2025. mcpress.mayoclinic.org
5. Pan A, Sun Q, et al. "Red Meat Consumption and Mortality: Results from Two Prospective Cohort Studies." Archives of Internal Medicine. 2012. pmc.ncbi.nlm.nih.gov
6. Cleveland Clinic. "Is Red Meat Bad for You?" February 2024. health.clevelandclinic.org
7. Mayo Clinic. "Eating processed, red meats — what are the health risks?" newsnetwork.mayoclinic.org
8. FutureCeuticals. "Fibermaxxing: A Trending Cue for Gut-Health Innovation." futureceuticals.com
9. Liversidge BD, Gomez DE, Dodd SAS, et al. "Comparison of the fecal microbiota of adult healthy dogs fed a plant-based (vegan) or an animal-based diet." Frontiers in Microbiology. April 2024. pmc.ncbi.nlm.nih.gov
10. Coelho LP, et al. "Similarity of the dog and human gut microbiomes in gene content and response to diet." Microbiome. 2018. doi:10.1186/s40168-018-0450-3.
11. Waltham Petcare Science Institute / mSystems. "Response of the gut microbiome and metabolome to dietary fiber in healthy dogs." January 2025. pmc.ncbi.nlm.nih.gov
12. Veterinary Practice. "What is the impact of dietary fibre and prebiotics on the microbiome and gastrointestinal health?" February 2023. veterinary-practice.com
13. Liversidge BD, Dodd SAS, et al. "Extruded diet macronutrient digestibility: plant-based (vegan) vs. animal-based diets in client-owned healthy adult dogs." Frontiers in Animal Science. November 2023. frontiersin.org
14. Liversidge BD, Dodd SAS, et al. "The fecal metabolomic signature of a plant-based (vegan) diet compared to an animal-based diet in healthy adult client-owned dogs." Journal of Animal Science. January 2025. academic.oup.com
15. Dodd S, Khosa D, Dewey C, Verbrugghe A. "Owner perception of health of North American dogs fed meat- or plant-based diets." Research in Veterinary Science. December 2022. sciencedirect.com
16. Lund EM, et al. "Prevalence and risk factors for obesity in adult dogs from private US veterinary practices." International Journal of Applied Research in Veterinary Medicine. 2006.
17. Bosch G, Verbrugghe A, Hesta M, et al. "The effects of dietary fibre type on satiety-related hormones and voluntary food intake in dogs." British Journal of Nutrition. 2009. cambridge.org
18. Weber M, Bissot T, Servet E, et al. "A high-protein, high-fiber diet designed for weight loss improves satiety in dogs." Journal of Veterinary Internal Medicine. 2007. pubmed.ncbi.nlm.nih.gov
19. Pilla R, Suchodolski JS. "The Role of the Canine Gut Microbiome and Metabolome in Health and Gastrointestinal Disease." Frontiers in Veterinary Science. December 2019. frontiersin.org