Recently, I got a dog. Or rather, I came into a dog. We did not mean to adopt her — my boyfriend and I were fostering her, which is where you provide temporary housing to a dog until the dog finds a more permanent situation — but then seven months passed and she was still curled up in our living room. So now I have a dog.

Our adjustment to cohabitation has been fairly painless. She likes to walk, and so do I. She likes to nap, and so do I. Sometimes she hides behind the couch, and while I don’t, I would if I were 14 pounds and dog-shaped.

What we cannot agree on is how to eat.

I am mostly vegan, and my boyfriend is always vegan; when we’ve fostered dogs, we’ve fed them vegan dog food, and they’ve been fine with that. I mean, I think. They have eaten it, often with enthusiasm, which I have attributed to the fact that it is food and they are dogs. But this dog, our dog, would not eat our hippie vegan dog food. This dog wanted meat. Is that so wrong?

Should a dog be vegan? There are compelling reasons to say yes. The environment, for one: American dogs and cats eat roughly a quarter of the animal-derived calories consumed in the US each year, according to UCLA geographer Gregory Okin. By his calculations, our pets’ current diets are responsible for as much as 64 million tons of greenhouse gases each year. For context, that’s about what you’d get driving 13 million cars for a year.

The traditional counterargument is that while sure, meat is tricky, a lot of what goes into pet food is animal byproduct — stuff humans won’t or can’t eat. So isn’t it better if it goes to feed pets? Isn’t that actually less total waste? To some extent, yes: As long as there’s a meat industry, there are byproducts from it, and it’s not like most humans are eating much bone meal.

But the problem, as Okin points out, is that the whole premise relies on relatively limited ideas about what constitutes scrap. “I’ve traveled around the world and I’m cognizant that what is considered human edible is culture-specific,” he told the Washington Post. At least some of what goes toward feeding pets could, with proper processing, go toward feeding people. It would be much nicer if dogs and cats were fuzzy recycling centers, but they aren’t. Pets, he argues, consume resources.

But let’s put environmental impact aside. Isn’t it fundamentally weird to adopt a rescue dog — at least in part because I want animals to have the best and most humane lives possible — and then feed her other animals? I love moral consistency almost as much as my dog loves gnawing on dried pig ears.

The pig whose ear she gnaws — it was a gift! — was almost certainly smarter than my dog. The reason she is a companion animal and the pig is food isn’t her intelligence, is all I’m saying. I adore my dog, but yesterday, I watched her hide from a floating plastic bag and then attack a skateboard.

Obviously, you can love your dog and eat a hamburger. But pets illustrate how deeply strange this is, that some animals are friends and some are food, and which qualifies as what is a function of culture rather than logic. Because, as Harold Herzog, professor emeritus of psychology at Western Carolina University and author of Some We Love, Some We Hate, Some We Eat, points out, “they’re all edible.”

Designated “pet food” is a relatively new concept. Special feed was once reserved for caged birds and goldfish, says Katherine C. Grier, a history professor at the University of Delaware and author of Pets in America: A History. Dogs, on the other hand, ate “what the family ate.” Which meant scraps: leftover meats and fish, bits of bone, along with vegetables and starches, sometimes served straight, and sometimes incorporated into a dog-specific stew.

In the early 1860s, a British company called Spratt’s Patent Limited introduced the original dog biscuits. According to legend, and the New York Times, the concept of a dog-specific cracker was born when Ohioan James Spratt ventured to London and observed “quayside mongrels feasting on hardtack, the dry biscuit that fed sailors on long voyages.”

At the time, Grier says, the British military was experimenting with putting meat into biscuits, an attempt to improve battle rations. Spratt saw another market: dogs.

The biscuits were expensive, aimed at people who were feeding large packs of elite hunting dogs and, later, fancy show dogs. The original Spratt’s Patent Meat Fibrine Dog Cakes “a mix of grains, beetroot, vegetables, and ‘the dried unsalted gelatinous parts of Prairie Beef,” which seemed to suit discerning canine tastes: “My greyhound, Royal Mary, winner of Altcar of last year’s Waterloo Plate,” read one testimonial, “was almost entirely trained for all her last year’s engagements on them.”

Until the 1930s, most dogs were still mostly eating table scraps, but the commercial pet food industry was on the rise. Americans were increasingly interested in reforming their own diets, which trickled down into the feeding of their pets. Advertising from the ’20s and ’30s positioned commercial dog food as not simply the pragmatic choice, but the progressive one, the thoroughly modern diet of the 20th-century dog.

“The time is past when the dog is brought up entirely upon the scraps,” advised Pet Dealer magazine in 1928. “Most dogs so fed are prone to obesity and some give off strong odors because of the highly seasoned or too fat or perhaps too starchy foods.” (That prepackaged dog food really took off during the Great Depression suggests another benefit: It was cheaper.)

“It really is the beginning of this idea that we can treat our dogs to a healthier diet like what we’re pursuing for ourselves,” Grier tells me.

If you go to a pet store today and browse the dog food aisle, it’s hard not to see it as a reflection of our current food obsessions, except instead of ripped men illustrating the medical and aesthetic benefits of protein powder, it’s shiny-coated Irish setters.

We live in an age when pets have unprecedented status. They are family members. They wear designer coats and receive subscription boxes. Last year, the research firm Mintel reported that pet owners — pets may be family, but they are also, in the US, property — spent $86.7 billion on their animal companions.

But the more we identify with our pets, the less sense it makes to keep them. With every passing study, the richer their inner lives seem to become; brain scans suggests dogs have what we’d recognize as feelings. “The logical consequence is that the more we attribute them with these characteristics,” Herzog once told the Guardian, “the less right we have to control every single aspect of their lives.”

On the phone, Herzog outlines what that means: “You’re taking away its right to choose its own food. You’re taking away its right to enjoy a sex life if you, for example, have it spayed or neutered, which is what most animal lovers do. I’m more morally conflicted about being a cat owner than I am about anything else.”

There are now all-raw diets, the dog equivalent of Paleo for people. Grain-free dog food exploded in popularity — something to do with preventing dog allergies, but while analysts trace the concern back to a 2007 pet food recall, it also seems to parallel a general panic about carbs. Hasn’t your dog read Wheatbelly? Except that then, this summer, the Food and Drug Administration announced it was investigating a potential link between grain-free diets and canine heart disease. Maybe grain-free diets are actually bad for dogs!

Even aesthetically, dog food — which, the author David Grimm points out, is always “food” and never “feed” — is inching ever closer to food for people. “We’re trending more into the space of having our pet food look a little more like our food,” Dana Brooks, the president of the Pet Food Institute, which represents pet food makers, told the Atlantic.

It’s easy to make fun of this — there is so much human suffering in the world and millennials are buying bone broth for their dogs. But there is also a deep sweetness. “Maybe you can provide your pet something that looks similar [to what you eat] so you feel like you’re sharing a meal with your pet,” Brooks proposed. If dogs are such a big part of our lives, is it so wrong to want to feel close?

There’s an exercise Herzog used to do with his students. He’d ask if it was okay, ethically, to feed mice to a boa constrictor, and they’d agree it was. Then he’d ask about cats: Can you feed mice to a cat? Almost everyone said no. “This girl raised her hand, and she was violently opposed to feeding mice to cats. I said, ‘Why?’ And she said, ‘If my cat ate mice, she wouldn’t be like me.’”

What should a good dog eat? It turns out, we aren’t really sure.

“Most of what we know about their nutrition is by trial and error,” Greg Aldrich, a professor at Kansas State University focused on pet food processing and nutrition, tells me. “There have been some moderate concerted efforts to evaluate the nutritional requirements for dogs and cats in the last 50 years, but I’ll tell you that it pales in comparison to what we know about mouse or rat nutrition, or pigs or cattle.”

This shouldn’t be surprising. We don’t really know how people are supposed to eat either. In both cases, the reasons are pretty much the same: ethics, money.

As Aldrich sees it, part of the problem is well-meaning activists who oppose animal research. “What they fail to understand,” he complains, “is that we’re not doing animal research just to be mean to animals. We’re trying to figure out their nutritional requirements! And sometimes that means we have to feed an animal below their requirement.”

The other problem is funding. The federal government funds at least some amount of research on human nutrition through organizations like the US Department of Agriculture and the National Institutes of Health. “They [fund studies] for cattle and pigs and people,” says Aldrich, “but not for dogs or cats,” and the result is that a lot of what we do know about pet nutrition comes from research funded by pet food companies. “The pet food companies are by and large responsible for everything we know about pet nutrition today.” And if it’s somewhat self-serving, well, we know things that we didn’t know before, and isn’t knowing better than knowing nothing?

The vast majority of current dog foods on the market use animal products. “Can I create a vegetarian diet for a dog? Yes, I can,” Aldrich assures me. “They tend to be more omnivorous like you and I, but we can do a meatless diet. We have to pay very, very, very special attention, though, because they do have tendencies toward a more carnivorous physiology. Only today, knowing all I know about nutrition and all of the analytical techniques, would I feel comfortable feeding a dog a vegetarian diet.”

Would he put his own dog on a vegetarian diet? (Aldrich has a Labrador retriever.) He considers this. Probably not.

There are, so far, no longitudinal studies of veganism in dogs. But plenty of dogs seem to do just fine on vegan diets. Some vets advise against it. Others do it for their own beloved pets. It could be better than an omnivorous diet. Alternatively, it could be worse.

“Either way, pet owners considering this feeding strategy should consider the risks and keep in mind that their dog will be a bit of a guinea pig until we have more data,” Cailin Heinze, a board-certified veterinary nutritionist at the Cummings Veterinary Medical Center at Tufts University, told the Daily Beast.

“There are plenty of things that we should try to do even if nobody has ever done them before,” Jeff Sebo, head of the Animal Studies masters program at NYU, tells me. “And I think this is one of them.”

I can live with this uncertainty. Nutritional science is wrong all the time! What I’m troubled by is how much my dog hates this vegan food. In her defense: It smells weird.

It’s possible she would just prefer a different vegan pet food. Things are happening. The buzzy new brand Wild Earth recently launched a line of dog treats using koji (a fungus also found in soy and miso) as the primary ingredient, and plans to release a kibble next. (They’re also working on a lab-grown mouse meat for environmentally minded cats.) Technology could solve this, maybe. But it hasn’t yet.

Jessica Pierce is a bioethicist and the author of several books on the ethics of keeping pets, including Run, Spot, Run: The Ethics of Keeping Pets. She is herself a vegan; she’s still wrestling with the question of what to feed her dog.

“I kind of flip-flop,” she tells me. “I do think it’s morally and environmentally a better choice,” to feed your dog vegan food. But then there is the happiness of the dog. “It feels like a deprivation to deny them something that, obviously, is really pleasurable for them.” It would all be much easier if we knew more about how dogs should eat. But we don’t.

There’s a commercial for Blue Buffalo Wilderness dog food that features a goofy-looking terrier running alongside his wolf ancestors, which he can do because they are connected by “a desire for meat.” It’s very persuasive.

And it’s not untrue: The general thinking now is that gray wolves and dogs diverged from a common ancestor somewhere between 15,000 and 40,000 years ago, so, sure, my dog has distant lupine ancestors. But was she meant to eat like them? “I think it’s hard to ask the question, ‘What are dogs meant to do?’” Pierce says. Dogs as we know them evolved alongside humans. You can’t observe a puggle in the wild.

Still, my dog is passionate about meat, and I want her to pursue her passions. “Is it fair for us to deny them that? I don’t know,” Pierce says.

“Maybe with our dogs, it’s not all or nothing,” she suggests. “They could be mostly vegan but have a little bit of meat here and there, especially if they found it themselves.” It’s the same as the goal for most people: not no meat, but less.

The moral of this story is anticlimactic and ethically suspect: I gave up on the vegan dog food. Instead, we switched to fish. I know that fish have feelings, too, but it felt like compromise, and it seems to make her happy. So does eating rocks, though, so it’s hard to know.

According to a 2015 Gallup poll, 32 percent of Americans believe animals should be given the same rights as people, but only 8 percent identify as vegetarian or vegan. The more we treat our pets like people, the weirder it is to keep them in our homes and walk them around on leashes. I adopted a dog, and now I feed her other animals. I want to live a life in keeping with my purported values, but I also want a dog. “I think our life is just fraught with these inconsistencies,” says Herzog. “And we have to learn what to live with.”