Can I feed my cat a vegan or vegetarian diet?
If you are thinking about feeding your cat a vegan or vegetarian diet, your heart is in the right place.
But I’m here to tell you not to do it.
You might be concerned about the ethics of meat production, or its environmental impact. Maybe you think a vegan or vegetarian diet is healthier for your cat.
But cats cannot safely and healthfully live a vegan or vegetarian lifestyle. Cats need to eat meat to survive.
In this post I explain the science behind why cats can’t be vegans or vegetarians.
I also talk about the study that everyone is talking about that seems to prove me wrong.
What does it mean to be vegan or vegetarian?
Although they sound similar, veganism and vegetarianism are two different things, so let’s discuss them separately.
What is a vegetarian?
Simply put, a vegetarian is someone who does not eat meat, often for moral, health, or religious reasons.
But there is not one single diet or lifestyle that is “vegetarian.” People who eat or behave in many different ways may all call themselves vegetarians.
In general, vegetarians primarily eat plant-based foods, including vegetables, fruits, grains, nuts, and seeds. But some vegetarians will also eat dairy products, like milk and cheese, and others include eggs in their diets.
What is a vegan?
Like vegetarians, vegans do not eat meat. But vegans also do not eat dairy or eggs, and some vegans do not eat honey.
But veganism, for many, is more lifestyle than diet. For some, being a vegan means avoiding any behavior that involves the exploitation of another living thing.
For example, some vegans are careful about the businesses they support and the clothes and makeup they wear: no leather shoes or silk shirts, and no cosmetics that have been tested on animals. Some vegans will not visit a zoo or aquarium, or ride a horse.
Why would anyone choose a vegan or vegetarian lifestyle?
Vegetarianism and veganism are growing movements. One study showed that 9.6 million people in the U.S. follow a plant-based lifestyle, a 300% increase from 2004 to 2019. About 10% of Americans over 18 consider themselves to be vegetarian or vegan.
People have varying reasons for choosing these lifestyles, but they often center around four main considerations:
Environmental and public health reasons
The environmental impact of industrial meat production is real.
Raising farm animals for food contributes between 6% and 32% of all greenhouse gas emissions, depending upon how you calculate it. It produces an enormous amount of waste that contaminates the water supply.
It contributes to the spread of disease from the overcrowding of animals with weakened immune systems, and the creation and growth of antibiotic-resistant bacteria.
To some, the raising of animals for food is morally wrong because it requires the exploitation of living, sentient beings.
Industrial farming, by necessity, demands animals to be raised in tightly packed enclosures, leading to stress and antisocial behaviors, like tail-biting in pigs, and pecking in chickens.
Meat farming also involves the wholesale collateral killing of animals that serve no purpose, like male chicks on an egg farm. Animals that are not killed outright, live short, often painful lives that end at the slaughterhouse.
Slaughterhouses are no place for humans, either. The work is dangerous, sometimes fatal, and can be psychologically harmful. Many slaughterhouse workers toil away in inhumane conditions without benefits, job security, or a living wage.
Studies confirm the health benefits of not eating meat. For humans, a carefully-planned plant-based diet will not only meet all of our nutritional needs, but can be a way to reduce the risk of many chronic illnesses.
Vegetarian and vegan diets have been associated with lower levels of obesity, lower blood pressure, and a lower risk of heart disease, cancer, and Type 2 diabetes. A plant-rich diet has been shown to lower the risk of dementia and improve joint pain in arthritis suffers.
Certain religions that promote the idea of ahimsa (“do no harm”), or non-violence, include the practice of vegetarianism in one form or another. These include followers of Jainism, Hinduism, Buddhism, and the Seventh Day Adventist church.
Cats should not eat a vegan or vegetarian diet
While I have just enumerated many good reasons to become a vegan or vegetarian yourself, your cat should NEVER be fed a vegan or vegetarian diet.
Humans can live well on a careful vegan or vegetarian diet, but cats are not human.
Cats do not have the same digestive system as humans. They do not absorb nutrients the same way. A cat’s body does not manufacture or synthesize certain essential nutrients the way a human body can.
The effects of feeding a cat an insufficient diet might not show up for months or even years. By then, irreversible damage may have already been done.
Let’s discuss the reasons why cats make terrible vegans or vegetarians:
Cats have short intestines
Cats are “obligate carnivores,” meaning that they are required to eat meat. Their little bodies were designed to live off small animals and not a whole lot else.
Cats have relatively short intestines. This is because the animal-based foods they are supposed to eat are quick and easy to digest. Mice don’t really contain fiber. Fiber would require a longer digestive tract for extracting nutrients.
Cats have an intestine-to-body-length ratio of 4:1. Dogs, by comparison, have an intestine-to-body-length ratio of 6:1.
Dogs are omnivores, meaning they were designed to eat both meat- and plant-based foods. The ASPCA says that it’s possible, with careful planning, to keep a dog on a plant-based diet. But intestine length is one reason the ASPCA says that a vegan diet is not appropriate for cats.
Cats’ teeth are designed for eating meat
If you want more proof that cats were designed to eat meat exclusively, look inside a cat’s mouth (if a cat will let you).
While dogs have flat molars (those big teeth at the back of the mouth), cats have sharp molars.
Flat molars can grind up fibrous foods. Cat molars are designed for ripping off pieces of meat.
Cats need a TON of protein
A cat’s body requires much more protein than a dog’s body.
According to the Association of American Feed Control Officials (AAFCO), the minimum amount of protein cat food should contain, when all of the moisture is removed, is 26%.
Dog food, on the other hand, can contain only 18% protein, and still meet a dog’s nutritional needs.
While commercial vegan cat foods use plant-based protein sources like soy and pea in an attempt to meet a cat’s demand for protein, most, if not all, fall short. This is because even though plants contain protein, they don’t contain as much protein as meat does.
Cats can’t easily digest starches
In addition to short intestines that make digesting carbohydrates difficult for cats, cats make relatively little of a starch-dissolving enzyme called amylase.
Most mammals produce amylase in their saliva, to get a head start on digesting any plants that have been eaten. Cats are among the few animals that do not have amylase in their saliva, an indication that nature did not intend for cats to be eating plants.
Amylase is also produced in the intestines and pancreas. But a cat’s intestines and pancreas make relatively little of this enzyme.
Without enough amylase, a cat simply can’t digest much starch. Cats who eat too much starch will suffer with diarrhea and bloating.
Cats need amino acids only found in meat
Twenty-two amino acids form the building blocks of all the proteins in the body. Some animals, including humans, can synthesize certain amino acids if they are lacking in the diet.
Essential amino acids are those which an animal cannot synthesize and must get from food.
Cats have 11 essential amino acids that they must get from food. Taurine is the most important essential amino acid for cats, and animal products, including seafood, are the only natural sources of this critical nutrient.
Humans and dogs can make their own taurine, but cats can’t. When a cat doesn’t get enough taurine, bad things start to happen. Kittens experience developmental problems. The photoreceptors at the back of a cat’s eye stop working correctly, leading to blindness. A cat’s immune system is suppressed. Blood clots form.
And worst of all, cats who do not get enough taurine develop hypertrophic cardiomyopathy, in which the heart muscle becomes weak. HCM is potentially fatal.
Cats need the fatty acids and vitamins found mainly in meat
Certain fatty acids and vitamins that cats need, are abundant in animal flesh.
Cats who don’t get enough fatty acids, specifically, arachidonic acid, can suffer from immune system problems.
Cats must also get vitamin D from the livers and fatty tissues of their prey. We humans, by contrast, make our own vitamin D when our skin is exposed to sunshine. A diet deficient in vitamin D can lead to weak bones, a weak heart, and poor muscle condition.
Other nutrients are delivered through animal-based ingredients, including vitamin A, vitamin B1 (thiamine), vitamin B3, and vitamin B12.
Don’t commercial vegan cat foods provide these missing nutrients?
It’s true that most commercial vegan pet foods supplement their foods with lab-synthesized nutrients like taurine and omega-6 fatty acids from plant sources.
It’s also true that even non-vegan pet foods must add supplements to make sure that they meet the recommended levels for cat food.
The problem is that we don’t yet know if these manufactured additives are as easily absorbed as those naturally occurring in meat.
The other problem is that illnesses caused by missing nutrients don’t show up overnight. Diseases caused by a poor diet can take months or even years to appear. They can also be hard to notice at first, because cats are very good at hiding when they’re sick.
By the time a cat is showing signs of being sick, the damage from an insufficient diet might have already been done.
The pet-food industry is poorly regulated
The other issue is that the pet-food industry isn’t as well regulated as most loving cat guardians would like. The Regulatory Review, an online publication that reports on regulatory news through the University of Pennsylvania Law School, entitled their story on this topic, “Pet Food Regulations May Be More Bark Than Bite.”
Pet food is big business: the global market for pet food was estimated at 103.3 billion in 2023.
Although the Pet Food Institute, a trade group representing this huge industry of pet food and treat manufacturers would have you believe differently, regulations governing the pet-food industry are weak and poorly enforced. Many manufacturing and labeling guidelines for pet-food producers are voluntary.
In other words, when you are reading the label on a package of commercial vegan pet food, you won’t always know if you are getting what the manufacturer promises.
That’s risky when you’re entrusting the health of your beloved cat to what many consider to be a radical diet.
Scientific studies show some commercial vegan cat foods are inadequate
In the absence of sufficient regulation, some researchers have begun testing commercial vegan pet foods for the levels of certain nutrients. The results, for cat foods in particular, have not been particularly encouraging.
A 2020 Brazilian study of several vegan dog foods and one vegan cat food, showed that the vegan cat food had too little protein, potassium, arginine, and taurine. There was too much copper and zinc.
A 2021 German study of vegan dog and cat foods concluded that none of the foods tested fulfilled the energy and nutrient requirements for a complete diet for either species.
A 2021 Canadian study compared 26 commercial vegan pet foods against American and European diet recommendations from the AAFCO and the European Pet Food Industry Federation (FEDIAF). None of the cat foods met either organization’s recommendation levels for taurine, sulfur amino acids, arachidonic acid, EP and DHA, calcium phosphorous, and vitamin D.
But one study showed that cats eating a vegan diet were healthier!
Google the question of whether a vegan diet is good for cats and you will get links to dozens of articles reporting on this study:
I encourage you to read it for yourself.
This study surveyed 1369 cat guardians, 127 of which said they were feeding their cats a vegan diet.
The researchers asked these cat guardians about 22 different health problems a cat could have. They also asked about seven different “health indicators”: things like how often they took their cats to the vet, and how much medicine they were using with their cats.
The vegan cats seemed to be doing better!
Results showed that 42% of guardians of cats on a meat-based diet reported at least one health problem in their pets, while only 37% of cat guardians whose cats ate a vegan diet reported a disorder.
The vegan cats also scored better on all health indicators than cats on meat-based diets.
So how come I’m not shouting from the rooftops that all cats should be on a vegan diet?
The problems with the vegan cat-food study
There are three reasons why the results of this study raise more questions than they answer:
The results are not statistically significant
“Statistical significance” is, as you might have guessed, a statistics term. It quantifies whether a result was likely due to chance.
“Sampling error” is one of the reasons the results of a study might not be statistically significant. The fact that only 127 vegan cats were included in the study, suggests that the health-results difference between the two groups wasn't big enough for anyone to be certain that it's true.
In other words, it doesn’t mean that vegan cats are healthier. It means that these particular results can’t give you the answer to the question of whether vegan- or meat-eating cats are healthier.
The study was self-reported
In this study, researchers simply asked cat guardians about their cats. The answers they gave weren’t verified by researchers.
Had researchers examined the cats themselves, and their veterinary records, the results may have been different.
I’m not saying that cat guardians lied, but they’re not scientists and they don’t look at their own cats objectively. They might not have remembered a vet visit, or they may “feel” like their cats are healthier on whatever diet they are feeding them.
The cats’ diets were not controlled
Were some cat guardians supplementing their cat’s vegan diets with traditional kibble? It’s impossible to know with a study design like this one.
My conclusion about vegan/vegetarian diets for cats
I purposefully did not share my own dietary lifestyle at the beginning of this post. I did not want readers to see any bias in my conclusions about what I believe cats should be eating.
While I am not a vegan or vegetarian, myself, I eat a mostly vegetarian diet, and my grown children are vegans and vegetarians. In other words, I am knowledgeable about and sympathetic to the reasons why people choose these dietary lifestyles.
But for now, any cats that share my home will be eating a meat-based diet. I don’t believe that commercial cat foods are currently able to meet the unique dietary requirements of cats, and I don’t trust that regulators are providing the necessary oversight of the industry.
More importantly, I don’t think the research has caught up with dietary trends. In the absence of good, hard science, it’s impossible to know whether a vegan diet is better or worse for cats. The consequences of a diet lacking in essential nutrients are too dire.
That doesn’t mean that I won’t ever change my mind. Show me solid research about the safety of a vegan or vegetarian diet for cats, and a brand of vegan food that is healthful for cats to eat long term, and I will happily sing a different tune.
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Dawn LaFontaine is a lifelong animal lover who always seems to have a little pet hair in her keyboard. Her blog, Kitty Contemplations, helps cat guardians better understand and care for the special beings they share their lives and homes with. Her cat-products business, Cat in the Box, sells beautiful, well-made, and award-winning products that she designed to meet the biological needs of cats.
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