Can Dogs and Cats EVER Go Vegetarian?

Patty Khuly, DVM
Written by:
Published: October 26, 2010
Can Dogs and Cats EVER Go Vegetarian?

A version of this question hits my e-mail inbox at least once a month. They come mostly from concerned vegans or political foodies looking for alternative solutions to feeding animal protein to their pets. So it’s not so kooky a question as you might originally assume. Yet despite warm feelings with respect to my correspondents’ good intentions, the query does, however, deserve a definitive answer in the negative.

OK, so here’s where I earn myself the wrath of pet owners who are going to send me angry e-mails and heartfelt testimonials about how their vegan cat lived for twenty years (inexplicable unless lots of household rodents got knocked off along the way), and how their chocolate Lab’s allergies went completely away after a new vegetarian diet (I can explain that one, though I’d never recommend a long term veggie food trial).

Sure, I’ll heartily agree that dogs and cats can live without animal protein. The question is… for how long and how well?

But first, let’s compare apples to apples. Because many of the so-called vegetarian pet diets on the market do not completely eschew animal protein. Rather, they limit them to eggs and dairy, which I view as a significantly less draconian diet change than the vegan approach. And yet I’d still never recommend it.

So what’s my trouble with these diets?

Well, first up, the obvious: Cats are obligate carnivores. Offering them a vegan approach is about as biologically appropriate as feeding them granola bars. OK, so I exaggerate, but it’s not too far off.

For dogs, our understanding is murkier, given that studying wild dogs' anatomy, physiology and behavior tells us one thing (i.e., that they’re mostly carnivorous), and studying what domesticated lab-reared beagles can digest tells us another (i.e., that dogs digest vegetable protein better than we previously thought).

That said, even the beagle-wielding commercial pet food nutritionists who champion the benefits of soy protein and corn gluten are nowhere near recommending exclusively veggie diets. Most veterinary nutritionists have concluded that dogs are solidly omnivorous, with an emphasis on the kinds of foods their dentition would indicate they’re built to consume - that is, both cuspids for tearing and molars for grinding. Hence, a meat-based diet with other stuff thrown in.

Which is why I’ll not be pushing the dietary envelope with my patients, thank you very much. In fact, beagles being the most digestively capable example of any organism (with the possible exception of flesh-eating bacteria), in this case I think I’ll stick to what observing the natural world sans human intervention can teach us.

But what about people with religious issues, you ask?

It is one thing to source kosher or halal foods for your pet. It’s quite another to expect our pets to subsist on a vegan diet because we have a personal or political issue with consuming animal proteins.

After all, if you really want a vegetarian pet you can  adopt a rabbit, get a goat, consider horses or buy a guinea pig. There are plenty of vegetarian options for those who really want to share the experience with their pets. There is no need to inflict a biologically stressful condition on another species just because you happen to feel inclined towards such a diet for yourself.

Apples... and oranges. 


Dr. Patty Khuly

Pic of the day: "Sebastian Carrot - waiting..." by The Scream

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