- Dogs are omnivores, just like humans, but they need protein.
- Protein helps build and repair muscles and grow and maintain tissues.
- Chicken, beef, and pork are easily digestible, widely availability, and appeal to dogs.
- Protein supplements are generally not recommended for dogs.
Thousands of years ago, when the ancestors of today’s dogs lived in the wild, they ate mostly what they hunted—meat. But did you know they munched on fruit and plants, too?
Dogs are omnivores, just like humans. As dogs and humans evolved together over thousands of years, the dog’s diet started incorporating more ingredients that humans would eat, like root vegetables and grains.
Most foods contain some form of protein. In addition to all the vitamins and minerals they get from the ingredients in their food, dogs were also getting protein from unexpected food sources. How much protein do they really need to eat? Does the protein a dog needs have to come from a meat source? Here, we unpack everything you need to know about dogs and protein.
Why Do Dogs Need Protein?
Protein helps keep dogs’ bodies running smoothly. When consumed in adequate quantities, protein contributes to building and repairing muscles, growing and maintaining tissues, and carrying out a host of other essential activities throughout the body.
Dr. Tammy Owens, a board-certified veterinary nutritionist and assistant professor at the Western College of Veterinary Medicine, explains that dogs’ bodies can’t produce these all-important internal proteins without also eating protein.
But pinpointing dogs’ exact protein needs is complicated, says Owen. Rather than saying protein should make up a certain percentage of every dog’s diet, she calculates an individual dog’s protein needs based on their size and any medical conditions. In healthy adult dogs, she says, protein needs are based on metabolic body weight. A metabolic body weight is the amount of energy used by a dog of a certain body weight.
In addition to overall protein needs, there are also the amino acids to consider. “Amino acids are the building blocks of proteins,” says Dr. Joe Bartges, a board-certified veterinary nutritionist and a professor of medicine and nutrition at the University of Georgia College of Veterinary Medicine.
He notes that 10 specific amino acids are considered essential for dogs. They are “essential” because it is essential that dogs eat those amino acids in their diet. “The body cannot make these [amino acids] and so they must be provided in the diet,” he says. As a result, amino acid composition (the amino acids that make up pork vs. beef vs. other proteins) also factors into protein requirements for dogs. An amino acid profile for a food refers to how much of each amino acid the food ingredient contains.
Nutritionists take the amino acid profile information from a large variety of food ingredients and combine them to see which ingredients, when added together, satisfy the amino acids needed by the dog in a given day.
Bartges says that commercial dog foods “contain a mix of ingredients to help balance the essential amino acids.”
What Are the Best Protein Sources for Dogs?
Determining the best protein sources for dogs is more complicated than you might assume.
While most of us immediately think of meat mainstays like chicken, turkey, or beef, Bartges says eggs are considered the “gold standard” for protein, and Owens agrees, noting that they’re “highly digestible and highly bioavailable.” Still, Owens says that even eggs are not a “perfect protein”—that is, one that provides the exact amounts of all 10 amino acids that dogs need.
When it comes to protein in dog food, Owens says that the top protein choices for dogs are:
Owens explains that these proteins are easily digestible, widely availability, and have a taste that appeals to a dog’s palette.
Proteins for Dogs With Allergies
Bartges notes that while dogs can sometimes have true food allergies to specific proteins, food intolerances are more common. While a food allergy is an immune system (defense system of the body) response to a protein source, a food intolerance refers to an abnormal reaction to food that is not caused by the immune system.
Owen says beef and chicken are two of the more widely used proteins that may evoke a reaction in dogs. But she’s also seen pups who react to rabbit, duck, and “a huge variety of things.”
“What we consider ‘safe’ to feed dogs with food allergies depends on what they’re currently eating when they have the allergy and their diet history,” Owens continues. “Often we have to look for a protein that they’ve never been fed before—like kangaroo.” But she says that finding novel (never been fed before) proteins for allergic dogs has been getting harder, since many commercial dog foods now include previously rarely-used ingredients like rabbit and venison.
Because of that, many veterinarians are now recommending hydrolyzed diets for dogs with protein allergies. Bartges explains that a hydrolyzed protein is “one that is basically pre-digested into pieces too small to be recognized by the immune system.” As a result, dogs typically won’t react even when it’s a protein they’re allergic to in its original form.
On an allergy-related side note: both Owens and Bartges say that there are no reliable tests for food allergies in dogs. An elimination diet—where certain ingredients are removed completely from the diet before being introduced back in—is the only way to determine the presence of a food allergy.
Low-Protein Diets vs. High-Protein Diets for Dogs
Rather than thinking of any diet as low-protein, Owens explains that it’s more accurate to say low-er protein, since no dog should ever dip below their required daily protein intake.
Generally, “low-protein” means a diet that has an adequate amount of protein to maintain body functions and muscle mass, but not an excess amount, Owens adds.
According to Owens, veterinarians may prescribe a lower-protein diet for dogs with medical conditions that affect their liver or kidneys, since those organs help process protein in and out of the body. Some of those dogs may even do best on a vegetarian diet—sticking to eggs, dairy and vegetable proteins, which Owens says may be easier for their bodies to handle.
But again, she underscores that it “never does any good to limit protein below minimum daily needs, [because] then the body just starts stealing what it needs from other parts of the body.”
Owens says there’s a joke among veterinary nutritionists that super-high-protein diets “just make very expensive pee,” since all that superfluous protein gets removed from the body through a dog’s urine.
Still, there are times Owens may recommend that pet parents feed their dogs a higher-protein diet. One example is dogs who are on a weight-loss plan, since she’d want to make sure that while restricting calories, the dog isn’t also dipping below necessary protein levels.
Bartges says high-protein diets may be used for “high-protein-requiring life stages,” such as pregnancy, lactation, or growth. He also uses them with athletic dogs to help improve muscle mass, or with dogs recovering from a critical illness or trauma.
“Dogs can tolerate higher protein levels as long as the diet is otherwise complete and balanced,” Bartges adds.
Vegetarian and Vegan Protein Sources for Dogs
Want your pup to join in your meat-free lifestyle? Good news: “Dogs are carnivorous omnivores, and as such, can eat vegetarian or vegan diets as long as they meet or exceed the nutritional requirements,” Bartges says.
Vegetarian and vegan sources of protein can include:
- Kidney beans
- Garbanzo beans
- Nutritional yeast
There are many other food ingredients that can be used as protein sources, the challenge is to be sure that you are not accidentally depriving your dog of a few essential amino acids along the way.
While Owens agrees that both vegan and vegetarian diets are “theoretically very possible” for dogs, she’s more comfortable placing a dog on a vegetarian diet than a vegan one, since eggs and dairy are “highly digestible, good-quality protein sources that will meet the amino acid profile needs,” she says. Just be careful any dairy products don’t cause any stomach upset.
She also says that pet parents should closely track what their pup is eating if they pursue a vegan or even a vegetarian diet. In fact, she recommends working with a veterinary nutritionist, even if it’s just to select a commercial food. And always be sure, she says, that any diet you feed your canine family member has been tested for safety, animals fed the food have been monitored for potential health issues and that all animals fed the food were alive at the end of the trial.
Protein Supplements for Dogs
Owens generally avoids protein supplementation with her dog patients. A complete and balanced diet is one that provides adequate protein, she notes, so if you’re supplementing pure protein on top of that, “we’re unbalancing the diet.”
If a dog needs more protein than he’s getting, “generally speaking, the best thing to do is to find a diet that’s complete and balanced, but includes a greater amount of protein,” Owens says.
Bartges agrees that protein supplementation is not necessary in healthy dogs, and even in dogs who require extra protein, he says a higher-protein diet will do the trick. The only time he’d supplement protein—usually in the form of whey or casein powder—would be if a dog is losing muscle mass but requires a specific therapeutic (and low-protein) diet.