Can pets thrive on vegan diets? What a major review shows – Earth.com
07-25-2026
Can pets thrive on vegan diets? What a major review shows
BySanjana Gajbhiye
Earth.com staff writer
Plenty of dog and cat owners keep asking the same question. If dogs evolved from wolves and cats are natural hunters, can either one really thrive on a meat-free diet?
The booming vegan pet food industry is betting the answer is yes, with a market worth $27 billion in 2024 and expected to more than double over the next decade
A new review set out to test the science under that worry. The analysis included 31 studies on how well dogs and cats digest vegan, vegetarian and plant-based diets, then read them together
The work comes from Professor Andrew Knight, an animal welfare researcher affiliated with Griffith University‘s School of Environment and Science
Of the 31 studies, 22 examined dogs, two examined cats, and seven covered both
Why pet owners choose plant diets
Ethics and the environment drive most of the move toward these diets. Owners who cut meat from their own plates often want the same for the animals they feed
The scale behind that choice is enormous. One analysis estimated that feeding the world’s pet dogs and cats meat brings billions of farmed land animals into the food chain each year
Plant-based dog foods also carry the lighter environmental load. A recent life cycle assessment put beef-based food far above them on greenhouse gases and on land use
Why digestibility is key
Digestibility is a plain idea that carries real weight. It measures how much of a nutrient crosses from the gut into the body, rather than passing straight through
A food can list every vitamin on the label and still fall short. If the animal cannot absorb those nutrients, the printed numbers stop meaning much
This matters more for dogs and cats than for many animals. Both carry fairly short intestinal tracts, so food moves through quickly with less time to break down
The review treats this measure as the crux of the whole debate. If plant food breaks down and absorbs well, the loudest objection to it loses its footing
Where the doubt began
The old suspicion had a real basis. Cats are obligate carnivores, and dogs sit closer to omnivores, so their needs and inner machinery differ
Plants also carry some baggage. Compounds like phytates and trypsin inhibitors can block minerals or interfere with protein, while heavy fiber can bind fats before the body absorbs them
Some had argued that meat protein is simply easier to use. If that were true, pets on plant diets should show it in poorer health
Yet the health record has not backed that fear. A survey of more than 4,000 guardians found no consistent palatability gap, and a run of health analyses has mostly landed in favor of the plant-fed animals
What the diet trials found
Across the diets studied, plant-based food held up far better than the doubt suggested. The pattern was steady rather than lucky
Five studies measured digestion throughout the entire digestive tract
In every study, vegan and vegetarian diets cleared 80% for dry matter, 85% for organic matter, 80% for protein, 89% for fat, and 88% for starch and soluble carbohydrate
Those figures sit right alongside meat-based diets. In several head-to-head trials, the plant diets matched their animal counterparts on nearly every measure
“Current evidence indicates nutritionally sound vegan and vegetarian pet diets, and their main proteinKnight said
How single proteins measured up
The review also looked past whole diets to the proteins inside, and soy has the longest track record of them all. Its amino acid profile comes close to meat, which is part of the appeal
Soyr and protein, and above 90% for fat
Pulses did well too, with green lentils, chickpeas, yellow peas and navy beans all landing in strong territory
Newer proteins joined the list. One is a microbial protein called FeedKind, grown from a harmless bacterium, and it digested as well as many familiar ingredients
Wheat gluten beat chicken and poultry byproduct meal on protein digestibility in several dog trials
Cats, for their part, absorbed rice protein concentrate better as its share of the diet climbed
What processing changes
Ingredients alone do not tell the whole story. How a food is made can lift its digestibility or drag it down
Raw pulses hold onto anti-nutritional compounds that lower the digestion of amino acids like methionine. Cooking usually knocks those out, which is why most commercial extruded foods absorb well
But heat cuts both ways. Push it too far and it sets off Maillard reactions, the browning chemistry behind toast, which can lock up lysine and leave it useless to the body
The lesson for makers is a careful middle path. Match the processing to the ingredient, and pair proteins so a weak spot in one does not starve the whole diet
What still needs checking
The review reads as reassuring, though it does not pretend to be the final word. Most of the evidence sits with dogs, while cats have far fewer studies behind them
Nearly all the work involved healthy adult animals in controlled settings. Puppies, kittens, senior pets and sick animals remain largely untested, and so do ordinary homes rather than labs
The scope was narrow on purpose. It weighed protein and energy rather than every micronutrient, so vitamins and minerals still need their own careful accounting
Selecting the best pet food
“These findings support the use of carefully formulated vegan and vegetarian diets and challenge the notion that such diets are less digestible than conventional meat-based diets,” Professor Knight said
To choose the best food, he recommends for pet carers check product labels. “There should be a clear statement that the diet is nutritionally complete.”
“It should come from a good pet food company that can provide information about the steps taken to ensure nutritional soundness, such as working with veterinary nutrition specialists.”
The study is published in the journal Animals
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