By Jean Hofve, DVM

There are several companies and websites that promote vegetarian (no meat or fish) or even vegan (no animal products at all) diets for cats. These products appeal to people who have chosen a vegetarian or vegan lifestyle for ethical reasons, and want to apply the same principles to their cats.

As a feline veterinarian, I absolutely do not recommend trying to turn your cat into a vegetarian or vegan, but if you are determined to do so, here is my best guidance for you.


The three most commonly used products are: Wysong Vegan, Vege-Cat, and Evolution. There is also an Italian-made food, Ami-Cat, that our European friends are using.

Wysong Vegan clearly states that it is a supplement to be used with meat (either fresh or canned). It is not complete by itself. The website and packaging clearly state this, but unfortunately a lot of people don’t read the label very carefully. Please be aware that despite the name, this is not a vegan cat food! Using it alone will cause severe nutritional deficiencies.

Vege-Cat comes in a supplement that you can add to other foods, and in a kibble mix that you make at home. Because of the increased risk of urinary tract disease in vegetarian and vegan cats, Vegecat products contain a urinary acidifier (methionine) to help prevent urinary tract problems; and they also produce a separate supplement that amplifies this effect. James Peden and HOANA (Harbingers of a New Age) were the original pioneers of vegan pet products. Their products are thoughtfully produced and time-tested, but are not adequate for kittens, or for pregnant or nursing queens,. The book “Vegetarian Cats and Dogs” is an eye-opener.

Evolution makes canned and dry vegan foods for dogs and cats. While they take pride in the fact that they don’t use any slaughterhouse waste, they do use corn gluten meal and soybean meal. Many cats have difficulty digesting soy, which along with soy’s naturally high phytoestrogen content, makes this protein source inherently problematic for cats. Corn gluten meal contains about 60% protein, but also a large proportion of carbohydrates. Corn has a high glycemic index and is a key factor in the development of feline diabetes. In the U.S., 95% of soy and corn are genetically modified. (Unless it states that these items are organic, they are certain to be GMO.) Recent studies show that GMO products cause many health problems in rats, including cancer. The website claims their foods are nutritionally complete, but there is not enough protein in their canned cat food to meet the minimum guarantee for all life stages.

Evolution operates in an ethical gray area. Evolution’s owner illegally reproduced and distributed copyrighted literature belonging to a non-profit animal rights organization. Numerous requests (and later, demands) from the non-profit organization to stop using its materials were ignored until legal action was imminent. Even today, their website makes outrageous claims about extending pets’ lifespans that have no scientific basis in fact. Moreover, the website and label make a big deal over the use of “non-GMO oats,” but no such claim is made for the main proteins, corn and soy. It is virtually certain that there is GMO corn and soy products in the cat food.

Ami-Cat: Many cat guardians praise this food, but it is nearly 50% carbohydrate; not great for cats who rely on animal protein for optimal health. It does not appear to contain

Cats and Non-Meat Diets

Cats, of course, 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, in general, 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.

Cats have an absolute requirement for the nutrients taurine and arachadonic acid that are found naturally only in animal products, with one exception: a type of seaweed that contains arachadonate. Taurine can be chemically synthesized (although the process is so environmentally harsh that all synthetic taurine used in the U.S. is imported from China). These additives can be used to make a diet that is chemically complete. However, natural sources of taurine and arachadonic acid contain many other amino acids, enzymes, co-factors, and other complex nutrients that may also be important for the cat’s overall health. Science has shown us that whole-food derived nutrients are, in almost all cases, far superior and healthy than synthetic versions. For instance, ascorbic acid is the active ingredient in Vitamin C. However, natural Vitamin C contains many other components, including rutin, bioflavonoids, and other co-factors.

These diets all rely on chemical analysis to verify their nutritional adequacy. They follow the Cat Food Nutrient Profiles established by the Association of American Feed Control Officials (AAFCO) in 1990. However, these standards are ancient compared to current knowledge; and even when they are updated in 2016, they will still be relying on data that is already more than a decade out of date. Pet nutrition experts also agree that feeding tests are far superior to the Nutrient Profiles for assessing nutritional adequacy (although both are far from perfect). Many pet foods that met these Profiles have proven to be dangerously inadequate when fed long term.

Cats consuming meat have a naturally low urinary pH; vegetables and grains cause the urine pH to be alkaline, which can cause urinary crystals and stones to form. These can become life-threatening. While the food producers skim over this problem, the website Vegan Cats is at least honest about the risk. They recommend frequent testing of the cat’s urine pH to make sure it is remaining in the normal range (6.5 or less), and therefore less likely to create struvite crystals and stones in the bladder.

High carbohydrate diets (which vegetarian and vegan foods are by definition) are also considered by many experts to be the primary risk factor for feline diabetes. Excess carbohydrates also contribute to weight gain.

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. While there are many anecdotal tales of cats thriving on vegetarian and vegan foods, it is a path that requires great commitment and a willingness to be flexible on the part of the guardian.

The ethical dilemma

A a 20+ year vegetarian/vegan, and having worked as a full-time animal rights activist for two years, I understand the ethical reasons that lead people to avoid consuming many or all animal products. There’s no doubt that the intensive “factory” raising and slaughtering of cows, pigs, chickens, turkeys and fish is truly a hideous industry that causes a great deal of animal suffering.

If you are considering a vegetarian rather than vegan diet, a lacto-ovo vegetarian diet has more flexibility by allowing dairy products and eggs as protein sources. However, you should know that in terms of suffering, animals raised to be food themselves are actually better off than dairy cattle and egg-laying chickens, who live far longer and surely crueler lives as production machines, and still face death at the slaughterhouse when they are too worn out to be worth keeping.

The ethical dilemma comes home when we share our lives with pets who are by nature carnivorous, such as dogs, cats, ferrets, and reptiles. Of these, dogs are the most evolutionarily flexible. Dogs’ nutritional requirements are quite similar to ours, so it is not at all difficult to include them in our animal-friendly lifestyle.

There is also the moral question of whether we should slaughter one animal (chicken or cow) to feed another animal (cat or dog). As Dr. Michael Fox asked, “Can we justify using parts of many other severely deprived and prematurely killed nonhuman animals to maintain each individual cat’s well-being?”

Speaking strictly from a veterinary viewpoint, vegetarian and vegan diets for cats make me nervous. I have seen some very sick cats as a result of these diets. The consequences of a such diets can reasonably be expected to include obesity, diabetes, urinary tract disease, kidney disease, allergies, asthma, inflammatory bowel disease, liver disease, and more.

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.

Click here to learn what cats should eat.

See also:

10 Reasons Why Dry Food is Bad for Cats and Dogs

Homemade vs. Commercial Food for Cats (and Dogs!)

Homemade Diets for Cats and Dogs

Selecting a Good Commercial Pet Food

Switching Foods

The “Dangers” of a Raw Diet

Why Cats Need Canned Food