Plant-Based Diets for Dogs

Can I feed my dog a vegetarian or vegan diet?

The answer is: it depends. Dogs have dietary requirements for energy and essential nutrients, not for specific ingredients. No single ingredient includes all the essential nutrients in the appropriate amounts, so complete and balanced diets are composed of multiple ingredients that may be animal-based or plant-based, and are supplemented with vitamins and minerals that may be synthetic or from plants.

Vegetarian or plant-based diets aim to avoid meat-based ingredients, while vegan diets aim to avoid all animal products, including ingredients like eggs and honey. Vegetarian diets have been successfully fed to dogs and there are medical situations in which a vegetarian diet may be recommended for a dog. However, in all cases, it is important to ensure that the diet is nutritionally adequate to support the dog's life stage and overall health.

While dogs do not have a specific requirement for animal-derived ingredients, some essential nutrients are found in higher amounts in animal products than in plant-based ingredients. Thus, if feeding a plant-based diet, it is important that all essential nutrients are present in adequate amounts. Additionally, some characteristics of plant ingredients, such as their higher fiber content, can reduce how well certain nutrients if the vegetarian diet is not properly formulated.

How can I tell if a commercial vegetarian diet is nutritionally complete and balanced?

Studies evaluating the nutritional adequacy of commercial vegetarian diets have produced mixed results. Some studies suggest that dogs can maintain health on an appropriately balanced, plant-based diet, while others have identified nutritional deficiencies. Any nutrient can become unbalanced in a diet. However, vegetarian diets require particular attention because some nutrients are found primarily in animal-based ingredients and those can be more difficult to provide in adequate amounts. These critical nutrients include vitamin A, vitamin B12, vitamin D, calcium, phosphorus, arachidonic acid, EPA, DHA, and the amino acids methionine, cysteine, and taurine.

For a diet to be considered complete and balanced by the Association of American Feed Control Officials (AAFCO) guidelines, it must meet the essential nutrient requirements of the target life stage and species, and it must have a nutritional adequacy statement. A nutritional adequacy statement indicates that the diet was either formulated to meet your dog’s needs or it went through a feeding trial.

• If a diet is formulated for nutritional adequacy, it means that the food meets the dog’s nutritional requirements as calculated in a theoretical evaluation, but may fall short of those values when digested by the dog due to fiber content or other metabolic impacts.
• In a feeding trial, a diet is fed to the target group, which must maintain general health and a stable body weight throughout the trial period. This test may better evaluate digestibility and bioavailability of a diet; however, feeding trials are not exhaustive. An adult maintenance diet that has undergone a feeding trial has been fed to 8 dogs for about 6 months, and the dogs have been monitored for general health. Some health parameters are evaluated to give an idea of whether the diet is adequate or inadequate, but blood tests are not comprehensive.

Be cautious when concluding a vegetarian diet is nutritionally adequate based on minimal evaluation. Neither method of nutritional testing is foolproof. Diet formulation requires an understanding of the nutritional inputs from the ingredients as well as an understanding of the animal being fed.

It is important to research the commercial vegetarian diet being fed and the company that makes it. Ask the company:

• Who formulates their products and what training do they have?
• What quality assurance steps are taken to reduce risks of nutrient deficiencies?
• Can you provide a typical nutrient analysis of the finished product? Your veterinarian can help evaluate the information received, or they may refer you to a qualified veterinary nutritionist for assistance.

Can a home-cooked vegetarian diet be nutritionally complete and balanced?

Studies have evaluated the appropriateness of home-cooked diet recipes found online or in books and have consistently found nutrient deficiencies, whether the recipe was meat-based or plant-based. Even "complete and balanced" home-cooked diets provided by an experienced and qualified veterinary nutritionist can be subject to “diet drift,” in which the person making the recipe alters or omits amounts or ingredients, rendering it no longer balanced.

If you want to feed a home-cooked, vegetarian diet to your dog, discuss it with your veterinarian and engage the expertise of a trained, experienced veterinary nutritionist from the American College of Veterinary Internal Medicine (sub-specialty Nutrition) or the European College of Veterinary and Comparative Nutrition.

Why might someone choose a plant-based diet for their dog?

Some may choose to feed a plant-based diet for religious, moral, or environmental reasons, or because of a perception of added health. Plants are excellent sources of fiber, which can help the large intestinal microbiome, and some plants have phytonutrients that provide benefits, such as additional antioxidants. Plants also tend to be lower in calories, so with added fiber and fewer calories, plants may help a dog feel fuller, and this is valuable for dogs on a weight management plan.

Some diseases may benefit from nutritional management with a plant-based diet. Some veterinary therapeutic diets are vegetarian, but not vegan, as they contain lanolin – a source of vitamin D3 and considered an animal product. Liver disease with hepatic encephalopathy is sometimes treated using a plant-based diet, as are some bladder stones. If your dog has a health condition, talk to your veterinarian to determine if a vegetarian diet is appropriate for your dog.

Environmentally-minded pet owners may wish to feed a plant-based diet for dogs as part of a smaller carbon footprint. If this is your goal, be sure to contact the food company directly to determine how their practices align with sustainability. Remember that packaging and shipping can have a significant impact on carbon output as well.

Are there nutritional concerns with feeding a vegetarian diet to a dog?

The essential amino acids methionine, taurine, and lysine are lower in plants than in animal tissues, so if a vegetarian diet is not properly formulated, it could be deficient in one or more of these nutrients. Some vitamins and minerals are also deficient in plants or found in lower amounts when compared to animal meats, specifically vitamins A, B12, and D, and minerals calcium, phosphorus, potassium, and zinc. For that reason, appropriate supplementation is necessary to ensure a plant-based diet is both complete and balanced.

In addition, young, growing dogs have increased nutrient requirements for the omega-3 fatty acid DHA. This fatty acid is essential for proper brain and vision development and is found mainly in marine sources (fish oils), but also in some marine algae. It is possible to provide vegetarian sources of DHA from marine algae but, as mentioned, it’s important to consult a pet nutrition expert to avoid nutritional deficiencies.

Lastly, plants have higher fiber content compared to animal products, which can provide good fuel for the microbiome, which is the group of bacteria that live in the large intestine. Fiber can also affect the digestibility of a diet. Increasing the amount of fiber can result in some nutrients being bound and not digested or used.

There has also been concern recently about potential diet-related dilated cardiomyopathy (dr-DCM). While the definitive cause of dr-DCM has not been determined, it is thought to be influenced by more than one factor and research is ongoing.

Dogs are descended from wolves, so shouldn’t they eat meat-based diets?

Dogs are indeed descended from wolves, but many adaptations have occurred between ancestral dogs over 50,000 years ago and the chihuahuas, beagles, and Great Danes that we keep in our homes today.

Domesticated dogs have existed with humans for 10,000 to 30,000 years and are considered omnivores. Dogs are part of the order Carnivora (family Canidae). Many other animals belong to the order Carnivora, including obligate carnivores (e.g., cats, lions, tigers) and herbivores, such as the giant panda, so animals in the Carnivora order are not necessarily strict carnivores.

Dogs’ genomes show distinct changes from their wolf ancestors that allow them to digest starches better, which allows them to better digest plant material. This adaptation also allows them to be classified as omnivores – able to eat both plants and meats.

Eating a diet that is “complete,” with all the known required nutrients, and that is “balanced,” with those nutrients in correct proportion to each other, is a standardized goal of AAFCO guidelines for pet food manufacturers in the USA. Both plant-based and meat-based diets can be unbalanced and inappropriate if they are not made properly.

Are any vegetables off limits?

Some foods should not be fed, even as treats, since they have been shown to be toxic to pets. Foods that should be avoided include alcohol, chocolate, macadamia nuts, garlic, onions, grapes, raisins, salty snack foods, and any food with xylitol artificial sweetener, such as some peanut butter products.

Remember that some foods that are tasty to a dog may also be high in calories and those extra calories can add up quickly. Two examples are sprayable cheese products or peanut butter, which should be used cautiously.

Also, if your dog has a diagnosed condition such as kidney disease, heart disease, or inflammatory bowel disease, some treats may not be appropriate. Fresh or frozen fruits and vegetables make excellent treats for dogs with kidney, heart, joint, gut, or liver disease because they contain mostly water, and they add nutrients like protein, fat, sodium or phosphorus to the pet’s diet. If your dog has a health condition, discuss treats with your veterinarian to ensure they are appropriate.

What are some good vegetables and fruits to use as treats?

Below is a table of fruit and vegetable ingredients that may be given as treats for dogs, with measured gram amounts and calories (kcal).

Important note: Your pet’s treat allotment (or allowance) each day should be no more than 10% of their total Calories eaten. For example, if your 25 kg dog needs 950 kcal per day to maintain a steady (or stable) body weight, then their treat allotment (or allowance) should be no more than 95 kcal per day.