Like many pet owners, Zoe and her husband feed their cat a scoop of dry food every day. But unlike most pet owners, the kibble they give their kitty isn’t made of meat—instead, it’s entirely plant-based. “I kept very quiet about it at first,” she says. You just never know how people are going to react to your dietary choices, even (or maybe especially) when those choices involve what you feed your pet.

Zoe, who requested to be identified by first name only to avoid online harassment, is part of a small but growing number of cat owners opting to feed their furry companions vegan kibble. These pet parents cite a wide range of concerns—from the environmental impact of meat to animal welfare to their pets’ health—as reasons for making the switch to VGRRR’s plant-based wet food, or Benevo’s Pawtato treats.

The rise of vegan cat food has drawn sharp criticism from animal welfare organizations, including the ASPCA. Some folks even assert that feeding your cat a vegan diet is tantamount to animal abuse. These opposing viewpoints have sparked fierce feline debate, and researchers who study animal health are left attempting to catch up with the trend.

Cat chow typically contains a slurry of slaughterhouse byproducts: organs like livers, kidneys, and lungs, as well as bits of the finer cuts, such as leg muscle. That’s mixed with pureed grains, vitamins, minerals, and veggies. The whole concoction gets extruded through a machine that pressure-cooks it into bite-sized, cereallike bits.

Whether or not you personally enjoy eating meat, the idea of feeding your beloved pet unidentifiable animal parts can be kind of upsetting if you think about it too hard. But those meat scraps are providing your kitty with absolutely essential nutrients. “Cats are what we call ‘obligate carnivores,’ ” says Andrea Harvey, a veterinarian at the University of Technology Sydney. “They physiologically have to eat meat.”

Specifically, cats need nutrients like taurine and certain fatty acids, which are abundant in animal flesh, because their bodies can’t synthesize them on their own. Humans, in contrast, are omnivores. If we cut chicken and steak from our diets, our systems can cobble together meat-specific nutrients from bits and pieces of molecules found in other foods.

Taurine-deficient cats suffer from a laundry list of ailments, including eye degeneration and a dangerous—and potentially fatal—heart condition called dilated cardiomyopathy. And cats who don’t get enough omega-6 fatty acids (particularly one called arachidonic acid) in their diets might suffer from immune system problems. Further, eating too much food that is not meat can be bad for cats. Cats can’t break down dietary starches easily, as their guts are relatively short, and they don’t produce very much of a starch-dissolving enzyme called amylase. This can result in diarrhea or bloating.

Vegan pet foods attempt to supplement their chow with the perfect balance of lab-synthesized taurine and omega-6s, as well as a ton of extra protein from plant sources. “It probably is possible to get those [essential nutrients] on a vegan diet if it’s really well balanced and put-together,” says Alexandra Whittaker, an animal welfare scientist at the University of Adelaide in Australia.

But whether Impossible Kibble can keep cats healthy in the long run is hard to say; the additives may not be as easy to absorb as their natural, meat-occurring counterparts. The maladies caused by a lack of essential nutrients don’t show up overnight. Instead, they can take months or even years to manifest, Harvey says. And even then, they can be hard to spot; cats are famously good at hiding illness. (There’s a reason the old cliché is “sick as a dog.”) These factors make it tough to study whether and when vegan felines may start to develop nutrient deficits.

Andrew Knight, an animal welfare and ethics researcher at the University of Winchester in the U.K., recently conducted a survey of more than 1,300 cat guardians in the U.K. The results showed that the 127 people who reported feeding their cats a vegan diet also reported that their pets had fewer vet visits and common disorders compared with folks who fed their cats a non-vegan diet. For Knight, the study is proof positive that cats can be perfectly healthy on a plant-based diet. “Our results reflect what real cat owners would see in real homes,” he says.

But for other researchers, the paper is far from conclusive. “That was a trend,” not a statistically significant result, says Whittaker, who was not involved in the study. She points out that the survey didn’t stipulate whether the vegan cats were fed an exclusively plant-based diet; some of the purportedly vegan kitties were indoor/outdoor cats who might indulge in the occasional mouse, for example. And other pet parents might still give their cats traditional food in addition to the vegan variety. Zoe, for example, supplements her cat’s plant-based meals with some meat-based wet food. Her cat is vegan-ish.

Further, since Knight’s was a self-reported survey, the results weren’t directly verified by the researchers—it’s possible owners weren’t accurately assessing their pets’ health. To really assess their physical condition, the researchers would have to look at the cats themselves, Whittaker says.

With so much uncertainty and potential complications, why go through the trouble of feeding your cat a vegan diet at all? For one thing, the environmental toll of meat farming is a doozy.

Although it pales in comparison to raising livestock for human consumption, commercial cat- and dog-food production emits a non-trivial amount of planet-warming carbon dioxide. One study found that food production for the U.S. pet population alone accounts for as much as 2.9 percent of agricultural CO2 emissions. Another study, of pets in China, found that their collective carbon “pawprint” was equivalent to that of up to 245 million people.

It’s also worth noting that, while feeding cats plants might be “unnatural,” so is feeding them kibble made of tuna, chicken, salmon, or beef—prey that they would never hunt in the wild. And even non-vegan pet foods must add supplements to ensure that they meet vet-recommended nutrition standards. “The pet food industry as a whole is quite poorly regulated,” says Harvey. Though things have improved markedly in recent decades, the reason we know so much about feline taurine deficiency at all is because many commercial cat foods in the 1970s lacked sufficient amounts of the nutrient. (Still, going with kibble is far better than attempting to feed pets a homemade diet, especially if you’re trying to get them to go vegan, Knight cautions.)

And then there’s the simple fact that we project onto our pets. We want them to be like us; if we’re eating plant-based food, it’s comforting to see them do the same.

For her part, Zoe worked very closely with her vet before embarking on a vegan meal plan for her cat. “Obviously, if I felt my cat would suffer on a vegan diet, I certainly wouldn’t do it,” she says.

But at the end of the day, given how little research has been conducted, most vets and animal welfare researchers wouldn’t recommend switching your cat to a fully vegan diet just yet. “There’s just not enough evidence out there to make a determination as to whether it’s safe for cats,” says Whittaker.