Can dogs and cats be vegan?

The objection

“Fine for you, but my dog and cat are carnivores. Forcing veganism on them is cruel.”

The answer

The objection puts dogs and cats in the same bowl, and the evidence separates them. Dogs have evolved to eat a more varied diet than their wolf ancestors, the British Veterinary Association (BVA) notes in its 2024 position on pet diets [1], and a 2016 review calls the domestic dog biologically omnivorous [3]. Cats are obligate carnivores [1], which makes them the hard case.

Can dogs be healthy on a vegan diet?

The evidence so far suggests a dog can stay healthy on a complete, well-formulated vegan diet, and in July 2024 the BVA accepted that “it is possible to feed dogs a plant-based diet” [1]. In October 2021 its president had said that although a vegetarian diet for a dog was theoretically possible, “we would not recommend it” [2]. The 2024 position still warns that these diets are hard to balance and that robust long-term data on their safety are lacking, and asks owners to monitor their dog’s health [1].

Most of the evidence comes from owners. In a 2022 survey of the owners of 2,536 dogs, led by Andrew Knight, 36% of the vegan-fed dogs were reported to have had a health disorder, against 43% of those fed raw meat and 49% of those on conventional meat [4]. On the survey’s general health indicators the raw-fed dogs appeared to fare marginally better than the vegan-fed ones, though they were significantly younger [4]. After adjusting for age, sex, neutering, breed size and exercise, the same team concluded in 2024 that “dogs fed vegan diets had the best health outcomes” [5]. Even then, the vegan-fed dogs were significantly more likely than raw-fed dogs to have had two or more vet visits in a year and to have moved onto a therapeutic diet, which the authors put down to raw feeders seeing vets less [5]. They were also more likely than dogs on either meat diet to have internal parasites, though only 9 of 279 had them [5]. Both papers were funded, the second in part, by ProVeg International [4][5], a group working to help the world become less reliant on animal agriculture [13].

A reanalysis of the same data by two University of Liverpool researchers found the vegan diet made a negligible contribution to whether owners saw their dog as ill, which turned mainly on its age, vet visits and medication (Barrett-Jolley and German, 2024) [6]. One of the two declared that his post is financially supported by the pet food company Royal Canin [6].

Direct measurements are scarcer: in a 2024 US study, 15 healthy adult dogs fed a commercial plant-based dry food for a year stayed healthy on vet examinations and on blood tests that included amino acids, vitamins and heart markers (Linde and colleagues) [8]. The study was funded by the Plant-Based Dog Food Health Study Initiative, and the dogs were compared only with their own results on meat-based food at the start, with no separate control group [8]. The first systematic review of the field, covering 16 studies of dogs and cats, found “no overwhelming evidence of adverse effects” but rated the certainty of most of the evidence as low or very low (Domínguez-Oliva and colleagues, 2023) [7].

Can cats be vegan?

A complete vegan diet for cats isn’t currently possible, according to the BVA’s July 2024 position, because cats are obligate carnivores and suitable synthetic essential amino acids are lacking [1]. Cats need taurine and preformed vitamin A, which the BVA said in 2021 are minimal or absent in plant ingredients [2], and arachidonic acid, an essential fat for them because they convert so little from other fats [10]. Synthetic nutrients already fill some of the gap in ordinary cat food: since a 1987 study linked low taurine to heart failure in cats fed commercial meat-based food, most pet foods have had synthetic taurine added (Knight and Leitsberger, 2016) [3].

The cat studies themselves are few, small and mixed. Among the six in the 2023 review, a 1992 experiment found that cats on a vegetarian diet lost about 87% of the taurine in their blood within two weeks, and a 2021 case report described two vegan-fed cats with anaemia and low folate [7]. Two other studies, in which most cats were on supplements, found taurine and B12 mostly within range, though one of them found low folate in about half its cats [7]. A later owner survey, published in 2023 and covering 1,369 cats, 127 of them vegan-fed, was also led by Knight and funded by ProVeg International [9]. Among the 988 cats whose owners reported a vet’s assessment, 37% of the 90 vegan-fed cats and 42% of the meat-fed ones had at least one health disorder [9]. Only one difference the survey tested was statistically significant, and it went against the vegan diet: kidney disease, at 4% of the vegan-fed cats against 3% of the meat-fed, though that rested on four cats [9].

In 2021 the BVA said that cats “should not be fed a vegetarian or vegan diet”, and advised anyone thinking of changing a pet’s diet to talk to their vet first [2]. Many vegans who live with cats face the harder question of buying meat for them.

What are the risks of vegan pet food?

For a dog, the 2023 review’s concern was nutrient imbalance, and it advised commercially made food formulated for the species as less likely to cause it [7]; for a cat, the BVA says no complete vegan diet yet exists [1]. Even commercial food can fall short. A 2020 laboratory analysis of the four vegan pet foods then sold in Brazil, three for dogs and one for cats, found every one short of at least one recommended nutrient, and the cat food had no arachidonic acid at all (Zafalon and colleagues) [10]. A 2026 systematic review of 54 laboratory studies of dog and cat food found deficiencies and excesses in every type, meat-based included, with only 10 of the studies finding none, though just six covered vegan food (Mace, Nicholles and Knight) [11]. The work was commissioned by the UK’s Sustainable Pet Food Foundation, with which Knight, who led the owner surveys above, is affiliated, and Nicholles consults for a pet food company [11]. The BVA advises anyone making a complete diet at home to seek advice from a board-certified veterinary nutritionist [1].

How many animals would vegan pet food spare?

Vegan food for the world’s pet dogs and cats would spare billions of farmed animals a year by one estimate, though the figure depends on how slaughter by-products are counted. A 2023 study by Knight put dogs’ and cats’ share of the farmed land animals eaten at nearly 9% worldwide in 2018 and 20% in the US in 2020 [12]. By its estimate, nutritionally sound vegan food for the world’s pet dogs alone would spare about 6 billion land animals a year; the study was funded by the Food System Research Fund and the pet food company Wild Earth [12]. By-products such as meat meal make up about half the animal ingredients in US dog and cat food, and Knight counts them, like meat, by the share of a carcass they make up, arguing that valuing them by their low market price understates their impact [12]. The BVA notes that many studies allocate emissions by economic value instead, so by-products count for less, and that pet food arguably stops them going to waste, though it also says animal ingredients usually have higher environmental impacts than plant ones [1].