Pets

Dogs and cats do as well or better on complete vegan food

By WhyStopHarmingAnimals.com

Dogs and cats fed complete, fortified vegan food are as healthy as those fed meat[1][2][3][4], and in several large studies they come out somewhat healthier[1][2][3][4][5]. The most recent systematic review found no convincing evidence of major harm[1], surveys covering thousands of animals point the same way[3][4], and digestibility research finds the food is absorbed about as well as meat-based food[6]. The condition is that the food is nutritionally complete[4][6].

The reviews

Domínguez-Oliva and colleagues searched Medline, Scopus and Web of Science for research on vegan diets in dogs and cats and found 16 studies (Veterinary Sciences, 2023)[1]. They concluded there was no convincing evidence of major adverse effects of vegan diets on dog or cat health, and some evidence of benefits[1]. It is the most recent full review of the literature.

Knight, writing in Frontiers in Veterinary Science in 2024, drew together ten studies in dogs and three in cats[2]. They found that vegan diets produce health outcomes as good as or better than non-vegan diets, with comparable palatability[2]. Claims that vegan pet food is nutritionally unsound don’t match what these papers found[2].

Thousands of dogs and cats

The largest studies are surveys of owners. In 2022 Knight and colleagues reported on 2,536 dogs in PLOS ONE[3]. Dogs on vegan diets had health indicators as good as or better than dogs on conventional meat diets[3]. Dogs fed raw meat looked slightly better on some owner reports, and vegan diets scored better than conventional meat[3].

A 2023 study of 1,369 cats, also in PLOS ONE, found that taking the results as a whole, cats fed vegan diets tended to be healthier than cats fed meat-based diets[4]. Only one of the differences reached statistical significance[4], so the survey shows vegan-fed cats were not worse off, with a lean toward better health[4].

A 2024 analysis of dogs (Heliyon) went further[5]. For six specific disorders, vegan diets were associated with statistically significant risk reductions of 50–61% compared with meat-based diets, in a large sample[5].

These are owner reports[3][4], and owner reports can be biased. The samples are large enough to count for something, though, and none of the surveys found vegan-fed animals worse off than those on conventional meat diets[3][4].

What has to be in the bowl

The usual objection is that cats and dogs are meat-eaters by nature. What an animal’s body needs, though, is a set of nutrients. Cats need taurine, vitamin A, arachidonic acid and B12 in their food, and fortified vegan diets supply all four. The research tested commercial, complete vegan food, not homemade guesswork, and that is the kind of food the results apply to.

Whether the animals actually absorb that food is a separate question. Knight’s 2026 review in Animals found that modern vegan and vegetarian diets for dogs and cats, and the protein sources in them, are broadly well digested and not normally significantly less digestible than meat-based food[6]. Taking the digestibility and health research together, the review concluded that the evidence points to nutritionally sound vegan diets with comparable or superior health outcomes[6]. Dogs, as Behringer and colleagues note, expanded their own starch-digesting amylase after eating human starch[7], while cats barely have it[7]. The digestibility findings covered both species[6].

Bramble

Bramble, a collie fed a plant-based diet, is widely reported to have lived to 25, about twice a typical collie’s lifespan[8]. The age is owner-reported, and it is not a Guinness record; the verified oldest dog is Bluey, an Australian cattle dog, at about 29[8]. One long-lived dog is an anecdote[8]. The reviews and the large surveys are the stronger evidence[8], and they say the same thing Bramble’s story suggests.

Dogs and cats need nutrients, and complete vegan food supplies them[2][6]. They do not need us to harm other animals to feed them.