Can Dogs and Cats Actually Digest Vegan Food? The 2026 Animals Review

Plant-based pet food used to be a fringe idea. In 2026, it is a $27 billion global market — and the science is finally catching up. A new review just published in Animals pooled 31 digestibility studies on vegan and vegetarian (“veg*n”) diets for dogs and cats, and the headline is simple: your dog or cat can digest a well-formulated plant-based diet about as well as a conventional meat-based one.

What the new study actually did

The review, authored by veterinary scientist Andrew Knight at Murdoch University and colleagues, was published on 9 May 2026 in Animals (16(10):1454). It systematically searched Web of Science and Scopus for every peer-reviewed study that measured how well dogs or cats digest vegan or vegetarian diets — or the individual plant ingredients used in them.

After screening, 31 studies made the cut: 22 in dogs, 2 in cats, and 7 covering both. The studies spanned a huge range of designs — apparent total tract digestibility (ATTD) feeding trials, ileal cannulation work, and in vitro models — and tested ingredients from soy and pea protein to chickpea, lentil, brown rice and even microbial proteins like FeedKind, made from the bacterium Methylococcus capsulatus.

The headline numbers

Across the five studies that measured ATTD of complete vegan diets, results clustered tightly above industry benchmarks for premium pet food:

• Dry matter digestibility: > 80%
• Organic matter: > 85%
• Crude protein: > 80%
• Fat: > 89%
• Nitrogen-free extract (carbohydrate): > 88%
• Energy: > 86%

For context, regulators and most pet-food formulators consider ≥80% ATTD the marker of a high-quality complete diet. Vegan formulations cleared that bar across every macronutrient measured.

Why the “short carnivore gut” argument is weaker than it sounds

The longstanding objection to vegan pet food is anatomical: dogs descended from carnivores and cats are obligate carnivores, so their relatively short intestines should struggle with plant antinutrients — phytates, trypsin inhibitors, oligosaccharides, fibre that binds bile acids. Knight's review confirms those compounds can reduce the digestibility of specific nutrients in raw plant ingredients. But modern processing (extrusion, dehulling, fermentation, enzyme treatment) largely defuses them, and finished veg*n diets behaved well in real animals.

This fits with what we already know about how processing reshapes the canine gut microbiome, and stands in contrast to the metabolic problems flagged in the recent 2026 BMC raw-meat obesity study.

What about cats?

Only nine of the 31 studies included cats, and the authors are appropriately cautious. Cats have higher requirements for taurine, arachidonic acid, vitamin A and certain B vitamins that plants don't naturally supply — so a vegan cat food has to be supplemented to be safe. Within that constraint, the digestibility data so far suggests cats handle well-formulated plant proteins better than the “obligate carnivore” narrative implies. But the evidence base is still thin, and the review explicitly calls for more feline trials before strong conclusions.

Health outcomes line up with the digestibility data

Digestibility is only useful if it translates to health. Knight's team summarises 12 separate analyses of dog health on veg*n diets published by early 2026 — 11 of them supported the diets, with comparable or better outcomes than meat-based controls. A UK nutritional analysis of 31 commercial dry dog foods found plant-based products matched their meat-based equivalents on most macro- and micronutrients, with iodine and B vitamins being the easy-to-supplement exceptions.

That broadly mirrors what we've covered in our pieces on blood biomarkers that predict canine lifespan and the IGF-1 study on large-breed cognitive aging — diet quality, not diet ideology, is what moves the long-term health needle.

What this means for owners considering plant-based pet food

1. Choose complete-and-balanced products that meet AAFCO or FEDIAF standards. The digestibility numbers above came from properly formulated diets, not homemade vegan recipes.
2. Look for soy, pea, lentil, chickpea, or microbial protein as the main protein source. These are the ingredients with the strongest digestibility data in the review.
3. Don't make cats vegan without veterinary supervision. Supplementation of taurine, vitamin A, arachidonic acid and B vitamins is non-negotiable.
4. Transition gradually over 7–14 days to let the gut microbiome adapt — the same advice we give in our healthy aging routine.
5. Recheck bloods at 6 months, especially for puppies, seniors, and any dog with a history of copper-related liver issues.

The bigger picture

The vegan pet food market grew from $10 billion in 2020 to $27 billion in 2024 and is projected to hit $57 billion by 2034 — roughly six times the growth rate of the conventional pet food market. With six billion land animals consumed annually just to feed pet dogs (and roughly a billion more for cats), the environmental case is enormous: previous modeling suggests transitioning all companion dogs to nutritionally sound vegan diets could cut greenhouse gas emissions by more than the entire UK's annual output.

The 2026 review doesn't claim plant-based food is the only ethical choice. What it does is remove the last big scientific objection: “dogs and cats can't digest plants” is no longer supported by the data.