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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.

8 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. :-)

    • 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.

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