Review finds vegan and vegetarian pet diets are generally as digestible as meat-based diets

A review of 31 studies published in Animals found that nutritionally sound vegan and vegetarian diets are generally digested as well as conventional meat-based diets by dogs and cats. The findings could ease concerns for pet owners weighing plant-based options, especially as the market for vegan pet food continues to grow.

Why it matters: - The review challenges a common concern that plant-based pet foods are harder for dogs and cats to digest. - Digestibility affects how much nutrition pets actually absorb, even when a food contains all essential nutrients. - The findings matter for pet owners considering nutritionally complete vegan diets, and for a pet food market valued at USD 26.9 billion in 2024. - The global vegan and plant-based pet food market is expected to grow by 7.8% annually.

What happened: - A review of 31 scientific studies found that vegan and vegetarian diets for dogs and cats are generally as digestible as meat-based diets when the diets are nutritionally sound. - The study was published in the peer-reviewed journal Animals. - Of the 31 studies, 22 focused on dogs, two focused on cats and seven included both species. - Study author Andrew Knight, an adjunct professor at Murdoch University veterinary school in Australia, said the evidence shows well-formulated vegan and vegetarian diets are generally digested efficiently by both dogs and cats.

The details: - The review examined research on the digestibility of vegan, vegetarian and plant-based diets and ingredients fed to companion animals. - The studies covered ingredients including wheat gluten, rice protein, soy-derived ingredients, peas, lentils, chickpeas, potato protein, quinoa and proteins produced through microbial fermentation. - Commercial vegan dog foods studied included products with peas, barley, oats, sunflower oil and lentils. - Some plant-derived nutrients were less digestible than comparable animal-derived ingredients in a small number of studies. - Overall digestibility remained high across the evidence base. - The review defined digestibility as a key measure of nutritional quality because it reflects how efficiently nutrients are absorbed and used by the body. - The study is titled The Digestibility of Vegan and Vegetarian Diets for Dogs and Cats. - The full study is available here.

Between the lines: - The review suggests the main barrier for many owners is not whether plant-based diets can work, but whether the products are properly formulated. - The authors noted that much of the existing research is on dogs, so the evidence base for cats is thinner. - Many studies also relied on pets living in normal household settings rather than laboratory conditions. - That leaves more uncertainty for kittens, senior animals and pets with existing health conditions. - The market backdrop shows rising demand driven by pet health concerns, environmental sustainability and farmed animal welfare.

What's next: - More research is needed on cats, as well as on kittens, senior pets and animals with health conditions. - The review points to a need for better evidence on how vegan and vegetarian diets perform in real-world feeding situations. - Pet owners considering these diets are advised to choose products labeled as nutritionally complete and made by manufacturers that can explain how nutritional adequacy is ensured.

The bottom line: - The review adds evidence that well-formulated vegan and vegetarian pet foods can be a nutritionally workable option for dogs and cats.