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Dogs Are Omnivores and Should be Fed as Such

Somehow the notion that dogs are pure carnivores has permeated through internet chat forums, among some non-medically trained people working in the pet industry (groomers, trainers, etc.), and those that take their information seriously.  This notion is based by in large on the multiply erroneous notion that dogs are essentially wolves, and since wolves are pure carnivores, then dogs necessarily should be fed as wolves would eat.

I stated multiply erroneous notion because the true fact is that EVEN WOLVES ARE NOT PURE CARNIVORES!  While it is true that wolves generally require and eat a high level of protein in comparison to dogs, they also consume a significant amount of vegetable matters instinctively, as doing so is necessary for optimal physiological balance and gastrointestinal health in the species.  Wolves consume vegetation from routine grazing on grasses and by tearing open the stomachs of their herbivorous prey and eating the contents.

The other true fact is that dogs are not wolves, but differ from the wolf in DNA structure by about 0.8 %.  That may not seem like much, but only a 1.2% difference in DNA separates us from the chimpanzee.  Few would suggest that we should model our diet around that of a chimpanzee.

Thousands of generations and selective breeding that made domestic dogs more adaptable to life with humans was responsible for the evolution that today differentiates dogs from their ancient ancestor.  Among the most prevalent difference between dogs and wolves that resulted is gastrointestinal physiology and how it impacts overall gastrointestinal and other organ health.  In the process of canine domestication, humans essentially their early more wolf-like canine companions what they ate, and over successive generations, the species adapted to a more omnivorous diet.

Dog owners jumping on board with feeding their dogs nothing but meat, essentially a pure protein diet, is fraught with potentially serious health consequences.  All one has to do is understand protein metabolism to see the problem.

Before protein can be absorbed into body’s cells and tissues for metabolic and physiological purposes, it must first be broken down into small chains of proteins called peptides, and in some cases broken down to the individual molecular protein building blocks, amino acids.  Once absorbed by the gut, amino acids and peptides are then repackaged and utilized by the body.

It all sounds lovely, but protein metabolism does not come without a price, as it generates a toxic waste product called ammonia.  In fact, many common meat protein sources are as low as 78% utilized by the body with the rest represented as waste.  Luckily, like us, canines have a liver that converts ammonia into a less harmful molecule called urea, which is then excreted by the kidneys in urine.

However, the liver and kidneys over time become overwhelmed with a diet heavily laden with protein, because these organs are constantly burdened with detoxification.  Over time, if excessively taxed in this manner through diet, these organs become compromised, leading to degenerative disease, chronic renal failure in the case of the kidneys, and cirrhosis in the case of the liver.

Physiologically, dietary protein for the average adult canine should not exceed 25% of the total daily nutrient intake.  In high performance dogs, such as those that participate in in field or agility competition, that requirement may be increased to 27%.  Beyond this level of  protein the dog suffers deficiencies in other key nutrients, such as soluble and insoluble fiber and anti-oxidants to name a few, while unnecessarily taxing his liver and kidneys with excessive protein metabolic waste.

Canine owners that feed raw are the biggest offenders with regard to overloading their dogs with protein, many feeding nothing but a raw meat diet.  For these pet owners that are committed to raw feeding, if they are feeding their dogs nothing but meat, I would urge them to integrate fresh or cooked vegetables to represent at least 50% of total dietary intake.  Green beans, carrots, broccoli, celery, and spinach are all healthy vegetable sources for dogs.  It is also a good idea to integrate complex carbohydrate sources, such as brown rice and sweet potato, as well as some canine safe fruits like cantaloupe, apples, and pears.

What is most troublesome to me is that some commercial pet food companies are taking advantage of the canine pure carnivore hype and creating diets that are heavily laden with protein, even going further to validate this false notion in their promotional tactics.  I was actually inspired to write this post after having seen a TV commercial two nights ago from a large, well known pet food company touting its newest diet as having one of the highest protein percentages in the industry.

I caution all canine owners to not buy into the hype, not listen to non-medically trained people that recommend a dietary regimen without understanding that over time it does damage to the liver and kidneys while denying the canine other essential nutrients; and reject pet food companies touting false claims, who clearly value sales far more than the well-being of their canine consumers.   If in doubt, talk to your veterinarian to help you sift through what is best to feed your dog.

Dr. Roger Welton is the President of Maybeck Animal Hospital and CEO/Chief Editor of the veterinary information and blog online community, Web-DVM.

16 thoughts on “Dogs Are Omnivores and Should be Fed as Such

  1. Mary Crawford says:

    You don’t know much about wolves. Wolves do NOT eat the stomach content of their prey. They rip the stomach open and shake the content out. This has been documented by wildlife biologists. Plus, I spent one year in Canada studying the eating habits of wolves and I never saw one wolf eat the stomach content of their prey. And even if wolves did consume the stomach content of their herbivore prey lets take a look at what these animals eat: grass, herbs, and leaves. They’re not vegetables!!! And what are the starch/carb content of herbs, grass, and leaves?: 0%, as oppose to vegetables like carrots 61 mg; potato 213g; squash 196g. So, to say wolves consume carbs and therefore dogs should too is total rubbish. Liver overburden by detoxing protein??? More rubbish. I’m glad I don’t get nutritional advice from you. Your article is total disinformation. How much is the Pet Food industry paying you to say this?

    • Dr. Roger says:

      I am so glad that you posted, as this is the exact “conspiracy theorist” rhetoric that propagates the internet. I have been a veterinarian for nearly 12 years, and have many veterinarian friends…and the notion that we are somehow in league with a pet food industry that gives us kickbacks and expensive vacations so that we base our nutritional advice on what they want us to say is beyond laughable. As much as those of your ilk want to believe that, it simply ios not true. Veterinarians actually by in large loathe the pet food industry, with no real oversight of the industry, they can feed you dog road kill, brand it as the greatest diet on earth, and no one is watching to call them out on it…except us.

      Contrary to what you conspiracy theorists choose to believe, most veterinarians chose this career path because we are generally good people who love animals. Any one of us could have far more easily chose human medicine and made at least double the money, with getting into veterinary school being 5 times more difficult to get accepted than medical school.

      Before I was a veterinarian, I got a bachelors degree in biochemistry, so organ physiology and evolution was well engrained for me well before I learned medical physiology and phygiological chemistry in my veteirnary ciruculum. What you call rubbish is well reaseached and scientific fact based on decades of countless unbiased, peered reviewed clinical studies and feeding trials. What’s more, modern evolutionary biologists in the study of how genetic code of the domestic dog differs from that of the wolf, have discovered starch assymilating genes that suggest that canine evolution in part was sparked by wolves adapting their diets to eat more like us. Here is an article discussing this point, it is by the BBC, who as far as I know, is not funded by the pet food industry:

      I am glad that you do not get nutritional advice from me as well…you clearly already know everything. :-)

      • James says:

        Wow, what a load of BS. Veterinary clinics do in fact (fact, yes fact) work hand in hand with certain dog food manufacturers, primarily Hills and Royal Canin. These companies “educate” vets on the nutritional benefits *choke* of their foods and offer a variety of rewards in exchange for their promotion. To deny this you are either an unethical vet or just a blatant liar.

        • Dr. Roger says:

          Fact, huh? I suppose you must have worked in every single veterinary hospital in the continental United States to be so certain of this “fact.” I appreciate you also knowing as fact that I am a blatantly lying, and/or unethical veterinarian without ever having even had a conversation with me, let alone met me in person or set foot in my veterinary clinic. Thanks for taking the time to comment…it was most enlightening.

        • Michelle says:

          These are the exact kind of vitriolic posts that make having an open and honest discussion in a forum too often devolve into a miserable experience.

          James “facts” are so untrue, it makes me seethe to read them. I used to work in Dr. Welton’s clinic and still bring my pets to see him because he is not only the most ethical, skilled and knowledgeable veterinarian I know, but one of the best people PERIOD that I know.

          Nobody, certainly the food companies that I never saw him give the time of day to when they called on him, dictates the type of medicine Dr. Welton practices, aside from new techniques and medical protocols he learns from all of the continuing education he constantly does.

          Another reason I continue to and always will being my pets to Dr. Welton is because he practices all facets of medicine, including holistic medicine. He controls acute pain and stabilizes his patients with traditional western medicine and surgery, but encourages owners to transition to techniques like acupuncture, therapy laser, and nutritional supplements.

          I also continue to work with Dr. Welton through a pet rescue I am passionate about, one of several that he donates his time and services to for nothing but love of the animals that he helps us save.

          People like you should really think twice before making generalizations about others simply because you disagree with an article; because if you knew the “facts” about Dr. Welton and his blessed hospital and how our community views him, you would regret having made them.

          Don’t let this person get you down, Doc, no matter how much good a person may do in life, there will always be haters. Thousands of pet owners on the Florida Space Coast and however many of your fans that read your blog and listen to you podcast know better!

          Back to James, before you decide to make any other judgement about Dr. W from afar, you should take a moment to visit his holistic web site:


          • Dr. Roger says:

            Michele, thanks. That was very kind of you, and please know that I have deep admiration for your group and the work you do for the unfortunate innocents in our community. As you well know, I am still waiting for that fully paid Hawaii vacation courtesy of the Hills corporation…perhaps if I even knew my Hills’ rep’s name, that may have come to fruition by now. :-)

            Best regards,

            Dr. Roger

    • Dr. Roger says:

      Wolves do indeed eat the stomach contents from their prey. Our county zoo that has red wolves and its veterinarian substantiate that. They also graze on grasses regularly. The carbohydrate component in grasses are much higher than I am sure you would care to believe, however, the truth is that as plant matter, then undergo photosynthesis, a process that turns water and carbon dioxide (catalyzed by UV light) into glucose. GLUCOSE is a CARBOHYDRATE. Believe what you want, but grasses are loaded with carbohydrates, which is why most of the starchy foods people eat – bread, cereals, beer, ect – are derived from grasses like wheat, barley and rye. Corn is a grass, selectively bred up from being a much smaller grass called maize to the large plant we see today – famously accomplished by Native Americans. So technically, corn too is a grass and is also very carb rich.

      If you do not believe that the liver has to work overdrive to process excessive protein, try feeding protein to a dog in liver failure and see what happens.

  2. Anon says:

    Thanks Dr Roger – finally someone speaking sense on this issue instead of the silliness regurgitated by many (well meaning) folks who happily accept so-called facts from non-experts (without any scientific backing), but somehow ignore the professionals!

    Case in point – one Raw dog food company website I looked at says this:

    “You will probably have come across the expression ‘as fit as a butchers dog’. This is a commonly used phrase to describe a person (or animal) that is in optimum health. The phrase itself derived from the fact that not too long ago, healthy dogs were fed from the butchers, not the supermarket. It was a well known fact that a dog fed on butchers scraps would be a very lucky (and well fed) dog indeed.”

    See how liberally the word “fact” is banded about without any evidence whatsoever. It gets worse further in, but that gives you a taster, so to speak.

    I implore all dog owners to buy the highest quality dog food they can afford, but don’t get taken in by the latest nonsense trends!

    • Dr. Roger says:

      Thank you for the thoughtful commentary. I will concede that there are some dogs that do better fed raw, and the risk of raw food pathogens is justified…however, for the optimal health of the dog, even thee cases should have a significant vegetable component to their diet. We have to look at each dog individually. Anybody claiming that one modality of feeding is right for every dog at every life stage is either being disingenuous or is simply rather misinformed. Again, thanks for taking the time to comment.

  3. Mr. Factual says:

    The fabric of our society is bull. It saddens me that so many people are deceived as usual. What God made, is simple as that. Yes God, and not evolution.Being a wolf biologist, and observing several subspecies; that would include: Iberian, Italian,Tundra, 3 different Canadian species, 1 Alaskan, giant Russian wolf species, the American Midwest wolves,and the red wolves of South Carolina, and coy wolves of New England. I serve on a holistic vet council and have 2 border collies, a real german shep, a corgi, and 2 wolf hybrids. I know beyond compare, that Canis Lupus Familiaris is a carnivore, period. 1 percent difference in wolves and dogs. Science has proven this. You people are so brain washed and want your beloved pet to be human like yourselvs. Even through time, the gut of the dog has not evolved. Only a small percentage of the brain and skull has. Having said that, When I feed my canines raw chicken leg quarters, and or whole rabbits some days, and ground venison and or beef with ground whole eggs another and an E400 with fish oil with them all,and with a liver of sorts maybe thrice a week, they thrive. Even on Orijen, Back to Basics, and Evo Dog Foods, they do exceptionally well. On other foods like Nutro, Eukanuba, and Blu; they did ok, not nearly as well or thrive. For one, Wolves do not eat stomach contents of their prey. However, cats do. Canines go for organs first. Wild Felidae will eat guts first. Also, cats do eat grass and berries in the wild. We’ve seen wild lions eat melons. This all what has been observed in the wild across the world. Also, science had been established. I said all of this to say that the physiology of the animal tells us things we know to be fact; couple that with natural life style of the animal, common sense will kick in. Note that grains and starches are in our cats foods and they do just as well on an omnivorous diet,let you people tell it. Something else we have observed in the clinics is that protein from plant sources are not equal to that of animal protein. I have so much data i cant share it all right now. But people, wake up and dont fall for the nonsense. In our clinics, we see sooo many dogs and cats healed just by being put on a protein based low carb diet. High and moderate meat based diets. Raw, dehydrated, and kibble. lOOK it up.

  4. Mr. Factual says:

    Let me add, most Vets dont get much education on nutrition while in school.

    • Dr. Roger says:

      I appreciate you taking the time to post, but having actually attended veterinary school, I will tell you unequivocally, that veterinary students receive a great deal of education in nutrition. It starts in first semester first year with species specific nutrient needs in a course called “Animal Nutrition.” In second semester of first year, moving on through the entirety of third year, we have physiology, which essentially tells us how the organ systems and biochemistry of the body works from the tissue, all the down to the cellular and molecular level. Nutrition and how it relates to these systems, how a proper balance or lack of proper balance per species affects these systems is frequently discussed.

      From there, we begin medicine and discuss disease specific nutrition, that is, how diseases are managed in large part nutritionally, eg., protein, phosphorus, and sodium restricted diet for chronic kidney failure. We learn to avoid copper rich diets for dogs with hepatitis from copper storage disorder, feeding diets heavy in L-Carnitine for dog breeds predisposed to dilative cardiomyopathy, and supplementing with omega-3 fish oils for management of arthritis, allergy, and autoimmune disease…to name but a few examples of disease management through nutrition and nutraceutical supplementation.

      Once veterinarians, we receive regular continuing education on nutrition. I consideration of all of this, this notion that we do not receive nutritional education in veterinary school and as practicing veterinarians, is clearly complete fabricated myth beyond calculation, and one that is propagated by people do not even know a veterinary, let alone experienced a veterinary curriculum first hand.

      • jium says:

        But if you spend so much time on animal nutrition at vet school, why so many vets still recommend cat owners to feed their cats with dry food when they know it’s full of carbs, low on animal protein and low on water? Stuff that can cause many diseases to felines? Don’t they teach that cats need water, animal protein and low carbs IN their food?

        I remember not once did the doctors at my local clinic say to switch my cat’s food from dry kibbles to at least wet food (cans or raw meat)!

        I had to learn like a dummy that dry kibbles is the worst BS to give to a cat. One did suggest to change from my Costco bag of kibbles to his Science Diet but I told him the Costco was cheaper. Three years ago, I have since made the transition to from dry to cans to raw meat and my cat is healthy and back to a normal weight. I also probably avoided potential urinary infections. It must have been a miracle that my cat didn’t get any in his first 12 years on that BS dry food.

        • Dr. Roger says:

          Thanks for taking the time to comment. Nutrition, like any other branch of science, is ever evolving. You make good points that simple carbohydrates are not good for cats, and we thus should be limiting their intake. On the other hand, while not a physiological requirement for optimal digestive health like dogs and people, many cats benefit from fiber in the diet, especially those that experience constipation issues as they age. As such, moderate amounts of vegetable complex carbohydrate and insoluble fiber are generally good for cats. Still. a feline’s diet should be most heavy in protein as, unlike dogs and people, cats are really a pure carnivore, in that their are capable of making any nutrient they need from protein. They are better adapted at synthesizing glucose from protein, which makes adding glucose in their food detrimental, increasing their risk of obesity, endocrine disease, and pancreatic issues.

          This unique understanding of feline nutritional physiology has been known for quite some time, yet the industry until recently has provided feline diets that are too canine like in their nutrient breakdowns. It was just not recognized enough, nor given enough credence until recently. True to the western approach to medicine, the focus has always been treat the disease once it manifests, but prevention and wellness through nutrition and lifestyle were not emphasized. That is rapidly changing for the better, just as it is in human health, where even we are recognizing that simple carbohydrates are not really good for us either!

          At any rate, these issues are not from lack of education, but more to the point less of a focus on how powerful nutrition really is. Cats need to be fed as cats and their evolution dictate. From my point of view, that would be 80% protein and 20% complex carbohydrate and insoluble fiber. However, there is nothing wrong with going 100% protein and adding fiber down the road in the event of GI issues (chronic vomiting, constipation, chronic loose stools, etc.). I also find that cats do well fed raw, with the risk of raw meat bacterial toxicity quite low. I would caution watching your sources of the raw meat, however. I did a three part series on raw feeding some time ago, that details the best sources of raw meat to feed animals that will minimize the risk of raw meat toxicity…take a look when you get a chance.

          The general notion that kibble is terrible for cats, however, I disagree as a blanket statement. With periodontal disease representing the second most common chronic disease in cats, good kibble technology is a powerful tool to clean the teeth the massage the gums. High quality kibble can fulfill ideal nutrient requirements for cats and need not be laden heavily with carbohydrate to achieve the necessary texture. Diets like Fromm, Innova, and Solid Gold are good examples of high quality diets that come in kibble form while staying true to the physiological nutritional needs of the feline. One draw back to these diets, however, is cost. In order to provide a species appropriate nutritionally balanced diet for cats and take as much carbohydrate filler out of the diet as possible, it makes the diets expensive (filler is cheap). The majority of kibble diets on the market, however, are not appropriately nutritionally balanced for cats, and the worst offenders are grocery store and super store brands of cat foods. It is these diets where your statement about kibble is true.

          • jium says:

            Thanks for the answer, doc.

          • jium says:

            Kibble no matter what brand, the cheap or expensive ones that you mentioned, are still too dry with its 10% moisture. You’re looking at higher chances, although not guaranteed, of expensive urinary infections.

            Better not take any chances and well hydrate one’s cat with cans with their 80% moisture or raw meaty bones.

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