Can Dogs Be Vegetarian? A Veterinarian’s View

Written by Dr. Rhiannon Koehler, DVM, MPH

As pet parents, we’re tasked with making decisions for our pets. We hope that we’re making the right ones.

For vegetarians, it’s common to wonder if your dog could join you in a vegetarian lifestyle, whether you’ve chosen vegetarianism for ethical, environmental, or health-related concerns.

In short, yes dogs can be vegetarians. But like many things in pet care, a simple “yes” or “no” answer doesn’t quite cover it.

Dogs? Wolves? - The Gastrointestinal Tract of Dogs and Diet Formulation

Regardless of what you might see in the marketing campaigns of several big-name companies, our dogs aren’t wolves anymore!

Domestication has changed the structure of their gastrointestinal tract, as well as their nutritional needs. 

While we think of wolves as carnivores, dogs are omnivores, meaning their preferred diet consists of both meat and plants.

However, like all animals, dogs require specific nutrients rather than specific ingredients.

This means a dog’s nutritional needs can be met without meat, though in some cases you may need to provide supplemental minerals, vitamins, or synthetic ingredients. 

A recent study comparing the genome of dogs and wolves found that ten genes with important roles in starch digestion and fat metabolism show important differences.

For example, wolves only have two copies of the gene for amylase, which is a protein that breaks down starch in the intestine.

In contrast, dogs have anywhere from 4 to 30 copies. The gene was also 28 times more active in dogs when compared with wolves.

Dogs have also evolved to subsist on a diet lower in protein.

 This research suggests that dogs are much better suited towards metabolizing carbohydrates than wolves.

The Pros of Vegetarianism for Dogs

When we think of the benefits and drawbacks of feeding a vegetarian diet, it’s important to note that the overall health impacts of a plant-based diet versus a meat-based diet are still being researched, both in humans and our canine companions.

As far as we know, most of the benefits of feeding your dog a vegetarian diet reflect your ethical values as a vegetarian pet parent.

In the United States alone, 34.3 million commercial cattle, 125 million hogs, and 2.07 million sheep and lambs were slaughtered in 2022.2 Over 9.5 billion chickens and 208 million turkeys were slaughtered in the same year.

The meat sources in most commercial diets come from the commercial slaughter of farm animals.

For some pet parents, this isn’t a concern. However, for vegetarian pet parents, knowing that their pet’s contribution to animal slaughter is reduced has a lot of meaning.

As far as your dog’s health goes, the jury is still out on the impacts of vegetarian diets.

In humans, plant-based diets are associated with fewer chronic health conditions. This may turn out to be true for our canine companions, too, but we cannot assume that because something is true for humans it must also be the case for dogs.  

Thus far, negative health impacts of a complete and balanced vegetarian diet haven’t been noted in dogs.

One recent study examining nutritionally balanced vegan diets found that they may be more beneficial than a conventional commercial kibble.

In this study, the researchers looked at the prevalence of 22 specific health disorders. Pet parents who had been feeding their dogs a conventional meat, raw meat, or vegan diet for at least one year reported back to the researchers on their pets’ health. 

The researchers found that 49% of dogs on a conventional diet and 43% of dogs on a raw meat diet suffered from at least one disorder compared to 36% of the vegan dogs.

Of course, these results depend on owner-reported observation, so there is some bias.

Furthermore, there were differences in the groups, with dogs fed a raw meat diet younger on average than the other two groups.

Much more evidence is needed to state whether a vegan or vegetarian diet has health benefits for most dog 

One known health benefit of a vegetarian diet relates to pups with food allergies. Contrary to popular belief, grains are NOT typically the cause of a dog’s allergies.

Typically, the protein sources in a diet are the leading cause of food allergies in dogs.

According to the Tufts University Cummings School of Veterinary Medicine, the top reported allergens are chicken, beef, dairy, and eggs. 

Consequently, feeding a vegetarian diet may be helpful in dogs with food allergies.

For folks feeding home-cooked diets to their dogs, vegetarian home-cooked diets also have the benefit of being more affordable than meat-based home-cooked diets.

Humans who eat a true vegetarian diet spend less money annually on groceries, so it makes sense that the same could be true for those of us feeding our dogs a vegetarian diet.

If you are home-cooking a vegetarian diet for your dog, make sure to see a veterinary nutritionist to ensure the diet you are providing is complete and nutritionally balanced.

The Cons of Vegetarianism for Dogs

While some pet parents may choose vegetarianism for their dogs due to their ethical values, the same can be said of pet parents who choose meat-based diets for their pets.

Questions these pet parents may ask themselves include:

• Is it ethical to put your moral values on your dog?
• Is it ethical to refuse your dog a preferred or natural component of their diet or one they have evolved to consume?

Evolutionarily, the dog does retain many traits that suggest they’re still adapted towards eating meat as part of its diet.

Dogs belong to the order Carnivora, meaning their ancestral counterparts subsisted primarily on prey.  

Examples of traits that suggest they are meant to eat meat as a component of their diet include: 

• Teeth adapted to tearing muscles and crunching bones
• Short intestinal tract more suggestive of meat digestion than plants
• Eyes sensitive to movement for catching prey
• Good dim light vision
• Superior sense of smell for tracking prey

These evolutionary traits helped dogs survive historically, but whether they are relevant to the modern dog’s lifestyle is a different question.

Again, we begin to blur the lines between ethics and science.

Protein quality is another important consideration for pet parents wanting to feed a vegetarian diet.

In many cases, the quality of proteins from plants is lower than the quality of protein from animal sources. 

When feeding a vegetarian diet, it’s important to ensure the diet is meeting the overall nitrogen needs and minimum requirements for amino acids.

A veterinary nutritionist is best suited for ensuring the diet is adequate.

Again, at this time, a well-balanced and nutritionally complete vegetarian diet appears to be safe and well-tolerated in dogs.

Would Dogs Enjoy a Vegetarian Diet?

It would be wonderful if dogs could speak to us and tell us how they feel about their food, but we can only make our best guess based on what we observe.

A recent study indicated that dog guardians didn’t report any difference in their pet’s appetite behavior when eating a vegan diet, conventional diet, or raw meat diet.

One can assume that this means a vegetarian diet rather than a vegan diet would be acceptable to dogs, as well.

How To Choose A Vegetarian Diet For Your Dog

The National Research Council (NRC) develops nutrient recommendations for dogs and cats in the United States.

NRC recommendations form the basis for the Association of American Feed Control Official’s (AAFCO) nutrient profiles for dogs.

AAFCO develops and implements laws, regulations, and standards for these diets. 

If you are planning to feed your dog a commercial vegetarian diet, ensure the food you pick has a nutritional adequacy statement specifying that the food was either formulated to meet AAFCO Dog and Cat Food Nutrient Profiles or that an AAFCO feeding trial was conducted.

If neither of these was completed, the food must be labeled as a snack, treat, or dietary supplement.

One study found that quite a few vegetarian diets listed as meeting AAFCO requirements actually failed to meet the nutritional adequacy and labelling requirements when evaluated.

However, the three vegetarian diets labelled for sale as prescription diets from a veterinarian all met the requirements.

If you’re considering a commercial diet, you could consider speaking with your veterinarian about which diets they would suggest.

Your veterinarian should have access to prescription vegetarian diets if that is your preference.

Home-cooked vegetarian diets are definitely an option!

The best way to ensure you are feeding a complete and balanced diet is to consult with a veterinary nutritionist.

Many veterinary nutritionists will work with you to develop a diet plan that meets your pet’s nutritional needs.

Feeding a diet that isn’t balanced can be quite dangerous for your pup, so make sure you’re working with a veterinarian to help your dog thrive.

References:

1.Knight A, Leitsberger M. Vegetarian versus Meat-Based Diets for Companion Animals. Animals (Basel). Sep 21 2016;6(9)doi:10.3390/ani6090057
2.Livestock Slaughter: 2022 Summarry (2023).
3.Poultry Slaughter: 2022 Summary (2023).
4.Espinosa-Marrón A, Adams K, Sinno L, et al. Environmental Impact of Animal-Based Food Production and the Feasibility of a Shift Toward Sustainable Plant-Based Diets in the United States. Frontiers in Sustainability. 2022;3doi:10.3389/frsus.2022.841106
5.Knight A, Huang E, Rai N, Brown H. Vegan versus meat-based dog food: Guardian-reported indicators of health. PLoS One. 2022;17(4):e0265662. doi:10.1371/journal.pone.0265662
6.Tufts University Cummings School of Veterinary Medicine Clinical Nutrition Team. What every pet owner should know about food allergies. https://vetnutrition.tufts.edu/2017/01/food-allergies/
7.Pais DF, Marques AC, Fuinhas JA. The cost of healthier and more sustainable food choices: Do plant-based consumers spend more on food? Agric Food Econ. 2022;10(1):18. doi:10.1186/s40100-022-00224-9
8.Hand MS, Zicker SC, Novotny B. Small animal clinical nutrition quick consult. Mark Morris Institute; 2011:294 pages : illustrations (chiefly color).
9.Knight A, Satchell L. Vegan versus meat-based pet foods: Owner-reported palatability behaviours and implications for canine and feline welfare. PLoS One. 2021;16(6):e0253292. doi:10.1371/journal.pone.0253292

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