A small but growing group of vegans advocate switching pets to plant-based diets. For many animal lovers, the most pressing reason for considering a vegan diet for their pets is the fact that most commercial cat foods and dog foods use meat, poultry, and eggs from factory farm sources, and factory farms are notoriously cruel to animals. However, concerns about companion animal health and environmental sustainability also play a role.
Cats Evolved to Eat Meat
Cats are known as obligate carnivores for several reasons:
- They have much higher protein and fat requirements than the majority of other mammals, and little need for carbohydrates.
- Many of the nutrients they require to live and thrive (such as taurine and arachidonic acid) are found only in meat.
- Unlike omnivores, cats can’t make their own vitamin B12 and vitamin A from plant matter, which means that they have to eat animals that can.
A cat’s natural diet consists of small prey such as birds, rodents, and in some cases small amphibians and reptiles. Other than the tiny amount of grass some cats consume and the partially digested plant matter they obtain from the digestive tracts of their prey, all of their nutrients come from meat. Cats that don’t consume these nutrients in sufficient quantities can suffer skin irritation, heart and liver problems, hearing loss, blindness, and even death.
There is plenty of evidence that cats evolved to live on an all-meat diet. According to Kirk, Debraekeleer, and Armstrong (2000):
- Cats don’t have receptors to taste medium chain fatty acids or sugars that are common in plant-based food sources.
- Cats have incisors and canine teeth for gripping prey and slicing tissue, and their teeth are less suitable than those of dogs for grinding up plant material.
- Cats have short gastrointestinal tracts, which don’t provide the extra time required to effectively digest plant-based materials.
- Cats don’t secrete some enzymes (and secrete very little of others) required to digest and derive energy from sugars commonly found in plants.
- Cats rely on protein more than carbohydrate for energy production (for omnivores such as humans and dogs, carbohydrates are a more important energy source).
- Aspects of the urea cycle in cats are designed to mitigate the risk of hyperammonemia, a potentially life-threatening condition associated with high protein diets in omnivores.
Can Cats Be Vegetarian or Vegan?
Makers of good quality vegetarian and vegan cat foods add synthetic variants of the missing nutrients that cats would normally obtain from meat. However, the majority of veterinarians, veterinary nutritionists, and animal organizations say that cats require meat for optimum health, though there are a few dissenting voices in the debate.
Rob Silver, DVM: “I think there are global, ethical and social reasons to feed our dogs and cats a vegetarian diet…[but] from a biological standpoint, there’s a need for dogs, and certainly much more so for cats, to have meat.” (White, 1996)
Rebecca Remillard, Veterinary Nutritionist: “Most of the vegetarian feline patients I have are on the scrawny side…They eat just enough to live.” (Wallace, 2008)
Andrew Knight, BSc. (Vet. Biol.), BVMS, CertAW, MRCVS: “Despite widespread prejudice against vegetarian pet food…there is no scientific reason why a diet comprised only of plant, mineral and synthetically-based ingredients cannot be formulated to meet all of [a cat’s nutritional] needs…Correct use of a complete and balanced nutritional supplement is essential to ensure the health of vegetarian companion animals, particularly cats. Regular urine pH monitoring is also important to detect and allow prevention of the urinary alkalinization, with its consequent potential for urinary stones, blockages and infections, that may result from a vegetarian diet in a small minority of cats.” (Knight, 13 July 2008)
Michael Fox, DVM: “I’m very concerned…about these vegan cat foods that read like a chemical soup with all these synthetic additives [to provide missing nutrients]. It’s getting so far away from fresh, whole foods that I think it’s ethically questionable and scientifically dubious.” (quoted in White, 1996) AND “…there is surely no scientific certainty that vegetarian/vegan cat foods will be good for all cats…To use the science of nutrition that is still in its infancy to support the feeding of vegetarian food to cats is to ignore the precautionary principle with regard to synthetically based ingredients, as well as the basic biology of the cat as a carnivore.” (Fox, 2005)
Tony Buffington, Professor of Veterinary Sciences, Ohio State University: “While it’s technically possible to formulate healthy nonmeat diets for cats and dogs, it’s complicated and something [Buffington] urges pet owners to consider very seriously. ‘Could there be vegan pets? Yes. Would I do it for my own animal? Never,’ he said. If he were to help someone do it…he’d make sure that the animal was a healthy, neutered adult. He would strongly advise against vegan diets for young, rapidly growing animals and those that are pregnant.” (Heussner & Berman, 2009)
Jean Hofve, DVM (Vegan and Animal Rights Activist): “Cats…were designed by nature to be exclusively carnivorous. The cat’s body has many specific evolutionary adaptations to its expected diet of prey consisting mostly of protein, fat and moisture. While cats have managed…to adapt to grain-based commercial foods, it is clear from many scientific studies that carbohydrate-based diets are in no way optimal for the feline…The truth is that science just doesn’t know enough about the cat’s nutritional needs to ensure the long-term safety of vegetarian and vegan diets for cats…Personally, I believe that when we voluntarily adopt cats into our homes, we are ethically obligated to honor the feline spirit and feed it according to its basic nature. But everyone needs to answer that question from their own heart.” (Hofve, 14 November 2010)
The Association of Veterinarians for Animal Rights (AVAR): “…until such time that a vegan diet for cats can be formulated so that there is no risk of harm to that animal’s life or health when fed that diet over time, cats should continue to be fed a diet containing animal flesh.” (WebArchive.org, 2006)
Opposing views on plant-based diets for cats are offered by the ASPCA and Stan Petrey, cofounder of the Home At Last Animal Shelter, where the residents are fed a vegetarian diet:
American Society for the Prevention of Cruelty to Animals (ASPCA): “At first, cats may appear to be doing satisfactorily on vegetarian or vegan diets…But over time nutritional deficiencies may occur. When it comes to felines, it really is best to provide a diet that includes meat.” (Jonas, n.d.)
Stan Petrey, Home At Last Animal Shelter (Kentucky): “…no diet-related problems have appeared in any of the cats, whose vegetarian status ranges from one year to four months…Beth Johnson, DVM, recently remarked, ‘The Home At Last dogs and cats appear in excellent physical condition…The cats…appear very healthy without any evidence of nutritional deficiency.’” (Knight, 13 July 2008)
VeganCats, which distributes cruelty-free products for companion animals, advises that certain cats should be fed some meat because many owners lack the time, knowledge, and resources to address the extremely complex nutritional and health monitoring needs of cats on vegan diets: “Unless you are very committed to following the advice outlined on our site…we recommend that you mitigate the risk of urinary tract problems by feeding male cats only a 25-75% vegan diet and females a 50-100% vegan diet…[although] many cats…will thrive on a simple vegan diet and never have any complications from urinary tract infections or crystal formations, you need to be prepared to adjust the diet accordingly for cats who may be prone to such issues.” (VeganCats.com, 2010)
Although I sympathize with the vegan cause, I don’t recommend vegetarian or vegan diets for cats at this time, given the lack of research into their long-term health outcomes, but I understand that some people feel very strongly about this issue. If considering a vegan diet for your cat, keep in mind that many amino acids and vitamins that are normally only found in meat are critical for cats, and without sufficient amounts, a cat can go blind or develop a life-threatening illness. Don’t attempt to implement a vegan diet unless you are willing to do all the research required to prevent nutritional deficiencies, work with a veterinarian who is knowledgeable on the subject, and monitor your cat’s health closely.
For those who are contemplating adopting a pet but hate the thought of feeding meat, there are plenty of naturally herbivorous animals such as rabbits, guinea pigs, iguanas, tortoises, mice, and hamsters that can be obtained from various shelters or rescue groups. For those who already own cats, there are ways to reduce the level of cruelty and environmental destruction that go into the production of meat-based commercial pet foods:
- Choose foods made from organic, free-range meats so that farm animals have the opportunity to live more natural, healthy lives.
- Visit farms to see how they treat their animals, purchase meat from the most animal-friendly farm you can find, and make your own pet food. (Note: this requires plenty of research and a large commitment of time and energy to ensure that the food you produce is safe and meets the cat’s nutritional needs).
For a full list of cat articles, see the main Cats page.
- AVAR. (2006). ” Vegetarian and Vegan Cat Food Diets.” WebArchive.org.
- Dunn, T.J., Jr., DVM. (n.d.). “Cats are Different.” ThePetCenter.com.
- Fox, M.W. (2005). “More on Vegetarian/Vegan Cat Foods.” Journal of the American Veterinary Medical Association, 226(7): 1047.
- Heussner, K.M., & Berman, J. (8 April 2009). “Can My Pet be a Vegan Like Me?” ABCNews.go.com.
- Hofve, J. (14 November 2010). “Vegetarian Cats?” LittleBigCat.com.
- Jonas, G. (2010). “Hold the Tuna: Is a Vegetarian Diet Safe for Your Cat?” GlobalAnimal.org.
- Kirk, C.A.; Debraekeleer, J.; & Armstrong, P.J. (2000). “Normal cats.” In: Hand, M.S.; Thatcher, C.D.; Remillard, R.L., et al. Eds. Small Animal Clinical Nutrition. 4th Edn. Philadelphia, PA: WB Saunders Co., 291-351.
- Knight, A. (13 July 2008). “Vegetarian Feline Diets.” Vegepets.Info.
- Max’s House Animal Rescue Inc. (2003). “Feline Nutrition.” MaxsHouse.com.
- Pierson, L.A., DVM. (2010). “Feeding Your Cat: Know the Basics of Feline Nutrition.” CatInfo.org.
- Scientific American. (12 March 2009). “Veggie Cat Food? Why Not All Cats Need Meat.” ScientificAmerican.com.
- VeganCats.com. (2010). “FAQ’s – Frequently Asked Questions.”
- Wallace, H. (2008). “Veg Pets?” Vegetarian Times, 356(March). Academic Search Elite database.
- White, L.B. (1996). “The Truth About Cats and Dogs.” Vegetarian Times, 231(November). Academic Search Elite database.