Should Dogs Eat a Vegan Diet?

Golden Cali watches puppy Orly bite an ice cream cone
A decidedly non-vegan treat!

A friend recently shared with me an article about feeding dogs a vegan diet. The article referred to two studies done in the UK with the same lead researcher. The upshot is that these articles say that dogs can live healthy lives on a vegan diet and that they find vegan diets palatable. In fact they claim that “vegan pet foods are generally at least (emphasis added) as palatable to dogs and cats as conventional meat or raw meat diets, and do not compromise their welfare.”

Color me skeptical. But I’m willing to consider the evidence.

Both studies were published by PLoS One (Public Library of Science), which means they are freely available:

The first issue with these studies is evident from their titles: Both are based on an online survey of dog and cat owners. The ‘indicators of health’ paper used a subset of the data used in the palatability study. Using a self-selected group of pet owners answering an online survey is not a scientifically sound method, and there’s no way to know whether the responses are accurate.

The questions are also problematic. To gauge dogs’ health, for example, they asked the owners to give their opinion of their dog’s health — and to also guess what their vet would say about their dog’s overall health … even for dogs whose owners report not having taken them to a vet in over a year (or ever).

There are other issues with the questions, such as the limited response choices for the kind of diet a dog ate — “conventional” meat-based, which covers an enormous variety of foods; raw, which could be homemade or commercial; and vegan, which also could be homemade or commercial — and not accounting for treats. A combination wasn’t an option, but I — and many people I know — feed some raw and some kibble.

Based on their data, though, the authors are certain that they know that dogs both enjoy their vegan diets and are generally perfectly healthy while eating vegan. (I haven’t seen a study on whether the cats on vegan diets were healthy … but it’s trickier with cats.)

I’m still very skeptical.

I actually do think that dogs can be healthy on a vegan diet, but it’s not easy. I think that, for an active dog, it would be challenging to provide sufficient protein from sources that dogs can easily digest without feeding so many carbs that the dog would become obese. (The study authors never actually saw the dogs, so we don’t know if the vegan-fed dogs were healthy weights.)

But what I am really skeptical of is the claim that the dogs (& cats) found the vegan diets “at least” as palatable as a meat-based diet. I simply do not think that dogs (or cats) want to be vegan.

As any trainer knows, some treats are “higher-value” than others.

While each individual dog will have different preferences, the highest-value treats tend to be the ones that are closer to fresh: fresh meat, fresh fish, cheese, even some fresh veggies. A close second is “jerky” type treats — dried meat or fish — or the soft treats. These smell and feel more like meat, and they probably taste more meaty (or fishy). Low-value treats are biscuit-type treats — cookies, kibble, Charlee Bears. These are hard and dry. They’re nicely crunchy, but I doubt they taste like much.

Within my dogs’ varied diet, they have favorite foods. Their behavior is very different when I am preparing them fresh food or mixing in canned sardines with their kibble than if I’m giving them plain kibble.

But they’re golden retrievers, so they greet any and all food eagerly, exhibiting some behaviors described in the study as indicating palatability and enjoyment, such as eating quickly, wagging their tails, and licking the bowl or their lips. Even non-golden-retrievers tend to eat quickly in multi-dog households, so this is not necessarily an indication that the dog likes the food.

Some of the other behaviors listed as indicating palatability are … at best, questionable. They’re also behaviors that I would not tolerate, no matter what they meant. These include vocalizing for food, stealing food, raiding food bins, waking the owner during the night for food, showing aggression around food, or staying near the food bowl. The last two indicate resource guarding, a whole separate problem that has nothing to do with the taste of the food.

The authors also say that the fact that the dogs ate the food they were served means that the food was palatable to them. But it could just mean that the dogs were hungry and knew that they weren’t getting a menu to choose their dinner from.

Or maybe it meant that the dogs were hungry because their vegan or kibble-only diet wasn’t satisfying. How do the authors know that the vocalizing dogs were asking for food? Or for more of the same food? Maybe they were literally crying for better food? And, how many dogs wake their owners up at night because they love their dinner so much they want more? Is that a thing?! Or were these dogs so hungry they couldn’t sleep?! Or they heard a strange noise or they were scared by the thunder or just wanted to cuddle …?

(In case you’re still wondering, I am pretty sure that the the study does not show what the study authors say it does.)

I’m also pretty sure that my dogs don’t want to be vegan.

To be fair, I am strongly in favor of a vegan diet. I am not vegan, but I inch closer to that ideal all the time. I also agree with the authors’ statements about the unsustainability of the way we feed pets. The whole food animal industry is unsustainable (and, I believe, problematic in so, so many ways).

Cali's pawprint looks like a smiley face
Cali’s pawprint; she’s a very happy girl

So, finally, we get to the real dilemma: Should I work toward my dogs’ happiness by feeding them a diet they enjoy and thrive on? Or should I follow the study authors’ ideals, which I share, of seeking a more sustainable option?

Cali and Orly vote for happiness.

Dogs and the Paleo Diet

Time for a snack! (photo by Sae Hokoyama)
Time for a snack! (photo by Sae Hokoyama)

Figuring out what to feed a dog never used to be so complicated. For generations, dogs simply ate whatever the people in the family ate. Or, to be more precise, whatever they didn’t eat — dogs were often fed the leftovers from a family’s meals.

Then came commercial dog food. Kibble, canned, semi-moist — all were convenient and were touted as much more healthful for our canine companions. Over the past 10 years or so, dog food has gone gourmet, with organic foods, human-grade foods, foods that cost more than the average family spends on groceries for the humans … but is it better for the dogs?

The latest fads are raw food and no grain or low carb diets, all touted as closer to dogs’ “natural” diet. The “natural” diet is defined by looking at what wolves eat. Wolves eat a high-protein diet, with lots of bones mixed in. They are opportunistic omnivores and will eat fruit, greens, and vegetables if they find them or if meat is scarce, but they thrive on a high protein diet. Carbohydrates can lead to inflammation, some argue, and aggravate problems, such as arthritis, that feature painful inflammation. Raw diets are easier to digest. The less processing the better. Dogs may have evolved considerably since diverging from their wolfish ancestors, but their digestive system hasn’t changed. In short, the Paleo Diet for dogs. (The Paleo Diet encourages eating lean meats, seafood, vegetables and fruits and avoiding dairy, grains, legumes and processed foods.)

Or so one theory goes.

Yet another theory points to a recent study that shows that, in fact, dogs’ digestive systems have changed as they’ve become our housemates— they’ve evolved the ability to process and use (small amounts of) carbohydrates more efficiently than their ancestors. Their life sharing the sofa and the remote with their couch potato humans has made them more amenable to snacking on (and digesting) potato chips. This could be a boon for dog food manufacturers who pack their products with inexpensive and starchy fillers.

This theory is based on research by evolutionary geneticist Erik Axelsson. He was looking for genetic differences relating to dogs’ and wolves nervous systems. But he found something surprising: He found that the three key genes involved in digesting starch are different in dogs and wolves.

While several theories are debated concerning how dogs became domesticated, all involve wolves spending enough time around humans — and humans’ food and leftovers — to form a relationship. That the wolves hanging out with the humans evolved to eat the kind of food the humans ate makes sense. (And hey, if our early ancestors were eating starch, doesn’t that make the Paleo Diet irrelevant and wrong? Pass the popcorn!)

Which theory is right? What should we be feeding Fido?

First of all, dogs are not wolves. In dog training, myths based on idea “dogs are the same as wolves”  have done untold damage to dogs’ relationships with their humans. Is the same sort of damage now being done to their health through misguided nutritional guidelines?

Modern humans eat a wider variety of foods than our long-ago ancestors did, and our bodies work differently — though a diet high in unprocessed, whole foods and low in simple carbohydrates is still the healthiest option. The same is true, I believe, for our dogs.

In a discussion of Axelsson’s study, PetMD.com’s Daily Vet blog recommends a balanced approach. If your dog’s diet includes grains, whole grains are recommended. Less-processed food is preferable to highly processed. Starches should only form a small part of the dog’s diet.

What might matter more than whether your dog’s food includes brown rice and barley or is completely grain-free is the quality of the ingredients and the relative proportions. As I wrote in “Ask the Thinking Dog” last spring, choosing a safe, healthful dog food can be challenging. I look for U.S.-sourced, high-quality ingredients and avoid food processed in any of the large pet-food factories that are the source of the never-ending recalls. Our dogs eat Fromm Family kibble and Sojo’s, but each dog’s needs are different, so you’ll need to figure out how best to meet your dog’s needs.

A word of caution: While discussing your dog’s diet with your vet is a good place to start, I have found that many vets strongly recommend foods that they sell — but that might not be the best choice for your dog. For example, several vets over the years have recommended putting our dogs on prescription diet foods, available only (and at extremely high cost) through the vet. In most cases, a “prescription” food is not necessary, and a higher-quality food can be purchased less expensively elsewhere.

Do your research! Understanding what proteins and other ingredients work best for your dog can help you choose the correct (non-prescription) food. Talk to the people at a locally owned (not big-box) pet supply store that sells a variety of high-quality foods. Often, these folks are quite knowledgeable. Talk with other dog people, and pay attention to how your dog’s energy level, digestive system, and skin and coat health are affected by different foods.