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Research Proves It: Dogs Thrive On A Starch-Rich Diet

Grains German ShepherdAt least that’s the propaganda that you are likely to hear since the publication of a fascinating study in the scientific journal Nature in January of 2013. The exact summary statement from the report actually says:

“Our results indicate that novel adaptations allowing the early ancestors of modern dogs to thrive on a diet rich in starch, relative to the carnivorous diet of wolves, constituted a crucial step in the early domestication of dogs.”

The underlying premise of the study is that for the wolf to transform into the dog, it had to adapt to the relatively high carbohydrate table scraps that humans had to offer. This adaptation necessitated genetic changes allowing for better starch digestion.

It’s tempting for those of us who favor low carb, raw, ancestral diets for dogs, to reject this research out of hand because it doesn’t conform to our beliefs. I propose that instead of sticking our heads in the sand, we need to face the findings and see what we can learn from them.

The study was conducted by a group of evolutionary geneticists from Uppsala University in Sweden. I have no doubt that these scientists know their specialty. It took me several hours to read every line of this study. I found the report to be very dense in content and rich in technical, genetic jargon, which made the details nearly inaccessible to anyone who doesn’t hold at least a PhD in genetics.

So in my subsequent online discussions of the research with my veterinary colleagues, I found that very few bothered to read more than the summary paragraph. I think the main reason for their complacency is that the conclusion of the study reinforced the conventional view of nutrition, so no critical evaluation was deemed necessary. Besides that, it was simply too difficult to read and comprehend. In this article, I’ll attempt to translate what I’ve learned from this study, interpreting the results as I go.

What Researchers Found

The researchers compared the DNA of 12 wolves from around the world with that of 60 dogs of 14 diverse breeds. They found genes that were different between the two groups and that had characteristics that indicated adaptation to new circumstances. Some of the mutations were in genes involved with brain development, which the researchers interpreted as relating to the less aggressive temperaments of dogs compared to wolves.

But the focus of the study was on other genetic changes that involved the digestive system. The researchers first established that the digestion of starch requires three steps.

The first step in the breakdown of starch requires the digestive enzyme amylase.

The second step necessitates an enzyme called maltase-glucoamylase.

The third step in starch processing requires a protein called SGLT1 to transport glucose from the gut into the bloodstream. The scientists proceeded to show to their satisfaction that dogs evolved away from wolves in all three of these steps.

Regarding Step 1, the researchers first found that dogs had between four and 30 copies of a gene that codes for amylase while wolves had only two copies. This indicated to them that dogs have a higher capacity to perform the first step in starch digestion. I agree it’s significant that dogs have between four and 30 copies of the amylase gene, and this wide range would indicate that some dogs are much less able to handle starch than others.

Next, they compared the expression of that gene in dogs versus wolves and found on average a 28 fold increase in dogs. They also tested the blood for enzyme activity and found a more than fourfold increase in dogs as opposed to wolves.

But one expert I talked to stated that increased gene expression doesn’t necessarily mean increased enzyme production. I would also add that the expression of such a gene as well as the enzyme activity would depend on the diet being fed. A high starch diet (most standard dog food) would turn on the needed genes as opposed to a low carb, wolf like diet. So the first part of the above work indicates that dogs have more genes for the first enzyme needed for starch digestion, but the second part proves nothing.

The researchers now moved on to Step 2. They didn’t find a higher number of genes coding for maltase-glucoamylase in dogs as compared to wolves. However, they were able to determine that there were significant differences in the gene responsible for that enzyme between dogs and wolves. They compared the canine mutations and found that when those same mutations occurred in other mammals, it often indicated a tendency toward the animal being omnivorous. They hypothesized that the gene mutations mean that in dogs, the enzyme is more effective at its job of digesting starch.

To test their hypothesis, the researchers measured the amount of maltase-glucoamylase in the pancreas and in the blood of dogs compared to wolves. They found higher levels in dogs. They admit that the difference in enzyme levels could be due to diet, and once again, the more carbs in the diet, the higher the enzyme levels are likely to be. Since wolves eat a low carb diet compared to most dogs, the researchers really did not prove anything conclusively about Step 2 of starch digestion, as far as I can see.

For the third step in starch digestion, the researchers focused on the gene coding for SGLT1 (the protein that transports glucose into the blood). They found that this gene too had mutations in the dog as opposed to the wolf. They then surmised that this change meant that the dog protein must be better at glucose transport. They showed that the dog version of SGLT1 is different than that of the wolf but did not prove that this difference is meaningful. Of course, if you believe that dogs evolved to handle starch better than wolves do, then it follows that this genetic difference proves your point.

This genetics study published in Nature attempted to prove that domestic canine DNA is different than that of wolves and that some of this difference indicates that dogs can digest and utilize starch better than wolves. They do show genetic differences but fail to conclusively prove that these differences mean that dogs “thrive” on a high starch diet.

Have Dogs Evolved To Eat Grains?

It really shouldn’t surprise anyone that dogs and wolves are not genetically identical. I have to admit that this research does suggest that dogs may be better able than their wild counterparts to handle starch in their diets. It is very likely that evolution is at work in domestic dogs when it comes to diet. But to really understand the ramifications of this statement, we need to review how evolution works.

No individual evolves from a genetic point of view. Instead, populations of animals evolve due to changes in living conditions they must adapt to. Rare individuals are born with a mutation that allows them to survive and reproduce better than all the others so that this new gene eventually (over hundreds of thousands of years) becomes the new norm.

I believe that when it comes to the canine diet, we are witnessing evolution in action. Rare, mutant dogs can somewhat handle the high carb diets we feed them, while the rest of the pets are sickened by them. After analyzing this study, I still think that ancestral diets are best for the majority of dogs.


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28 Responses to Research Proves It: Dogs Thrive On A Starch-Rich Diet

  1. Kimberley April 8, 2014 at 12:20 PM #

    Interesting article. My own experiences at home emulates that which was stated in the article. I have two mutts and one of which does not do well with any significant amount of grains in the diet. The other one does not seem to be affected by starches at all. I feed a lightly cooked home diet of 75% or more protein and the rest mix vegetables that have been diced and blanched. Both seem to do well with this blend. The grains they do get is in the homemade dog biscuits and the treats are offered relatively sparingly.

  2. Roger Biduk March 6, 2014 at 4:27 PM #

    Carnivores don’t eat starches, sugars or carbohydrates… if vets who only practice allopathic veterinary don’t understand that, they shouldn’t be allowed to sell pet food… especially garbage “prescription diets”.
    Roger Biduk

  3. WAKHINIB November 19, 2013 at 7:55 AM #

    I have breeds that are very ancient and in their country of origin ARE ONLY FED ON GOAT/SHEEP MILK and MILLET/BARLEY ETC – sorry folks, anyone wonder more about what the heck we happen spray on all these grains over our side of the world that may make them somewhat more intolerable for the digestive tract!
    I have fed raw for over 22 years, and will continue with my GRAIN A.M. REGIME despite what all you folks want to believe – they do indeed get their meat meal in the p.m. – I own natural, off the desert or off the plateau dogs that have lived for centuries with what they are provided – THESE ARE WORKING DOGS AS WELL – WORK OR YOU DON’T SURVIVE so we must all keep in mind that God made a variety of things to eat and while I understand and agree with many of the things said – don’t everyone just dis the value of grains and dairy – centuries of life in Turkey or Mali will prove otherwise.

  4. Jana Rade November 10, 2013 at 5:02 PM #

    This reminds me of an old Czech fairy tale, About Three Spinners (translation?). They were kind of fairies, spinning yarn and fate. They were doing it forever. On the old-style yard spinner. And their bodies were “mutated”. One had a huge over-sized tongue, one had an over-sized thumb and one had an over-sized foot, in order to best accommodate their job.

    I believe that it only makes sense, that after such a long time of consuming so much carbohydrates, dogs had to adjust to processing them. That is the body’s survival mechanism. The body evolves to best do the job it needs to do. It is logical and not surprising.

    The main question is, is it for the good of the dogs and what does the rest of the body think about it?

    Imagine walking with one foot twice the size of the other. Or eating or talking with an over-sized tongue. Or handling anything else than yarn spinning with an enormous thumb.

  5. june lay November 8, 2013 at 12:04 PM #

    I think there are many too variables to draw the conclusion that dogs cannot thrive on carbohydrates unless one is stating to the exclusion of protein and fat.

    first, domestication is the adaption to a changing environment, which first starts as behavioral. Over thousands of years, this results in necessary physiological changes, such as this discussion tries to analyze. What is fascinating is this, cats are also domesticated, although not as long as dogs living as close, and is is proven that cats are obligate carnivores. They do not use carbohydrates as their fuel source for energy, they use protein. Too much carbs and they more easily develop diabetes. Dogs do use csrbohydrate nutrients as their fuel source just as humans do.

    part of what is missing from this discussion is the type of carbohydrate, not are all equal, especially the grain type found in kibble. Also, just as in humans, there is a wide variance in genes and metabolism. I thrive on a milk product, my friend has lactose intolerance. Another friend has allergies, etc etc etc.

    I personally recommend a higher percentage of protein for dogs than for us humans, but I also recommend certain csrbohydrates and this amount is a higher percent than carbohydrates. Dogs can get kidney disease on a total protein diet and develop intolerances when feeding one source.

    I can go on and on, but I myself conclude that through thousands of years, dogs are not wolves, nor should be fed as one, nor trained as one either such ss the famous trainer.

  6. Peter G November 6, 2013 at 2:27 PM #

    Our companion dog, a long-haired German Shepherd Dog, is afflicted with exocrine pancreatic insufficency [EPI] He must have ONLY a grain-free diet, otherwise he is subject to Small Intestinal Bacterial Overgrowth [SIBO] In this case, of course, the dog does not produce ANY enzymes that could even begin to process starches, so he is on a strictly grain-free diet, with the addition of porcine enzymes. This affliction, while not fatal in and of itself, if treated with the enzymes, illustrates to me that dogs should not have any unprocessed grain. Eating the grain in their prey’s belly or intestines, is one thing, and, if I am correct, wolves have been observed to eat the intestines of their herbivore prey first, than the organs, then the muscle meat. But this grain is already at least partly processed and is not pure grain. I do not believe that the acidic structure of the canine intestinal tract is designed to process anything other than meat. Thus, they are carnivores, and to maintain strength, health, and energy, should be fed only grain-free foods!

    • Dogs Naturally Magazine November 10, 2013 at 9:28 AM #

      It’s been debunked that wolves eat the stomach contents of their kill – they don’t.

  7. Donna November 5, 2013 at 4:44 PM #

    Thank you for clarifying that research paper.
    I read an excerpt from “Science Now” myself and used part of it for my essay on “Carbohydrates Requirements and the Canine” What I got out of it in a nut shell is the same as you….dogs vary on what they can digest when it comes to carbs. I concentrated on the statement about the amalyse ranging from 4 to 30 in domestic dogs and wolves having only 2. Dogs evolved along with humans and just like us there are a large number of dogs that can’t digest certain foods, mainly wheat and dairy, properly or at all. I am lactose and gluten intolerant and 1 out of 3 of my dogs is as well.
    This was my first paper I have written since high school, a very, very long time ago, and I really enjoyed doing the research and learning. I’m so glad I get your newsletters and the subject was of huge interest to me. ( BTW, I got an A on that paper. :-))

  8. Lynn November 5, 2013 at 1:42 PM #

    They used 12 wolves vs 60 dogs of only 14 breed. That in itself doesn’t seem good for an accurate comparison. And as he points out, exposure can cause genes to express themselves, when they wouldn’t otherwise do so.

    It would be interesting to see the study replicated in a more controlled way. What about using some wolves on a ‘natural’ diet, some wolves on a kibble diet, some dogs on a ‘natural’ diet, and some dogs on a kibble diet.

    For the last 40 years or so humans have been eating diets with more and more processed sugars, especially high fructose corn syrup. People live long, active lives on these diets. But that doesn’t mean they’re in optimum health. And without medical interference, what would they be like?

    It’s the same for dogs. They eat garbage diets, but survive. And thanks to extensive veterinary care, they stll manage to live long lives. But that doesn’t mean the quality of their lives is what it would be if they’d been fed a natural diet their entire lives.

    • Michele November 6, 2013 at 6:26 AM #

      I think Lynn says it all and I would add that humans have evolved to eating meat … and what does that prove It’s important to remember that herbivores have 20 metres of intestines and humans have 10 metres and dogs only 3 being carnivores Nutrients come from the intestines and if you feed grains to your dogs then this bulk will need a bunch of stuff to make it palatable plus nutritious where as raw is easy to digest and includes no chemicals

    • Deez March 16, 2014 at 7:05 PM #

      AND they used wolves. There is a long term study being done in Russia which used foxes and wolves to see which were the origins of domesticated dogs. Using several generations of both wolves and fox, consistently they found the wolf pups, when raised as dog pups, consistently reverting back to the wild state of their ancestors. Fox were different. The pups tamed down when treated by humans as dog pups, those which didn’t get much handling remained wild. The fox pups grew trusting humans enough they haven’t reverted. As of my last check, the coats of the foxes were also changing and becoming more colorful with wide variety in color. As some may know, foxes are opportunistic eaters, they eat what they can find which includes grasses (read grass seed, which is grain), though not to the extreme western culture has taken it.
      I agree with some who say dogs can eat what is natural to their environment, a little grain which matches what’s natural to where they live. That’s if we want to keep them healthy w/o many visits to vets.

  9. CanadyAnna November 5, 2013 at 1:19 PM #

    Would be an interesting followup study to compare the results from coyotes who naturally have a more varied diet than wolves.
    One thing I do know, my std poodle wants nothing to do with carbs of any sort – turns up his nose at biscuits, grain based kibble even vegetables and fruit or the like. He knows what he wants and it is not carbs. Perhaps we should have named him “Atkins”!

  10. Betsy Cambareri November 5, 2013 at 11:25 AM #

    I have seen wild packs of dogs in Ecuador scavenging off of trash dumps. They have puppies, but for all intents and purposes these dogs are not healthy and thriving! They looked mangey,unhealthy! I have seen neglected dogs, skin and bones, still produce puppies. The fact that dogs perhaps have evolved the ability to utilize starch better than wolves does not necessarily correlate to thriving. It also doesn’t mean that they lost the ability to utilize meat as well as wolves. There are many questions this study did not answer.

    I have noticed that kibble fed dogs age horribly. When they are in their teens they often are rather decrepit. I was at UC Davis with one of my dogs recently and there were two labradors in the lobby that I thought were in their early teens but were in fact only 8 years old! My nearly 15 year old raised-raw Aussie still looks incredible and people comment that he looks really good for his age! My point being, just because an animal can reproduce and put its genes into the population when younger doesn’t mean that it is the fitter animal in the long run.

    The fact that being able to utilize the available food source better than wolves started the ball rolling to domestication which furthered the dependency, but to make the leap from being able to utilize an available food source to “thriving” on it is a big one!

    • LeeLee November 5, 2013 at 1:29 PM #

      Great reply, Betsy! And also great article, Doug – I enjoyed the read and didn’t want it to end! I’ve fed my dogs raw for years, and include a ménage of leftovers, cooked meals, etc. I will always view dogs to be primarily carnivores with scavenging tendencies.. Not that this Upsala study is touting the contrary.., just confirming that their digestive system has evolved to such a point, due to the influence of human domestication, to be able ‘handle’ starches if the dog so chooses to ingest, say, a bowl of rice noodles.. ;D

  11. tfg November 5, 2013 at 11:15 AM #

    It would have been interesting to see the results of testing dogs who are fed an all raw or high protein and low carb diet and then compare them to dogs given high carb processed kibble and also compare them to wolves! That would have been a complete study…

  12. luna November 5, 2013 at 10:48 AM #

    Would like to know what dog breeds were used. As an owner of 3 types of Northern Breeds including CSV none can eat more then a small handful of starch, without any problems arising but are gluten free. However raw green tripe included in their diet is a good choice for us. I am not going to change their diet but keeping to their ancestors and environment diet and one is nearly 16yo and only visited vet 3 times.

  13. Judy J. November 5, 2013 at 10:44 AM #

    I would love to have known what breeds were studied and the findings/breed. I have a Shih Tzu, which is more closely related to wolves via genome mapping. That would make me think that he is less able to tolerate/use starches (which he is not fed).

  14. Amy November 5, 2013 at 10:27 AM #

    threenorns has a valid point. Whenever my dog has something with grain in it he becomes ill. His skin will break out and on comes an ear infecton. When he eats his raw diet he is without issues. I also notice on a raw diet he does not have fleas. Nor do ticks wish to attach themselves to him when we take our nature walks. His breath is fresh and he does not have odor to his body. He does not pass gas like so many commercially fed canines do. So there is no need for me to question if he can handle starch or not. He has shown me he cannot.

  15. Mariska Jansen November 5, 2013 at 10:12 AM #

    Thank you for the article! I also advise my clients to feed their dogs raw meat (I advise the commercial ones with vitamins etc.). After reading your article, I will advise the same, but maybe some more nuanced.

  16. Yankee Shelties November 5, 2013 at 10:07 AM #

    As scavengers, dogs (like us) can get by on lots of food sources, But it isn’t the best for them in the long run. I do feed my dogs a small amount of carbs which seems to keep them in good weight, but it is a minor portion of their diet..

  17. Lisa November 5, 2013 at 9:55 AM #

    So, what foods should we feed them? What would be best for them in a kibble form?

    • Dr. Doug Knueven November 6, 2013 at 4:06 PM #

      I hate to tell you but the best kibble is no kibble. Making kibble required starch plus processing which destroys nutrients and creates carcinogens. The ideal diet is a balanced raw/ancestral diet.
      Dr. Doug

    • Heidi November 7, 2013 at 10:51 AM #

      Lisa, you should look into Raw feeding. All kibble, even grain free, is so incredibly processed that the nutrients that dogs need are cooked right out of it. If you’re going to invest in some expensive kibble you’re better of just getting them cuts of meat from the butcher. Personally, I get a lot of hunting leftovers and my guy is eating elk and deer these days. It takes a freezer and a bit of time but the health benefits you’ll see…WOW! There’s a raw feeding group on yahoo you can join to learn more or just google it, that’s how I found out about it!! rawfed.com is a great place to start:)

  18. threenorns November 5, 2013 at 9:52 AM #

    the only thing i need to know is this: when my dog gets into bread, he farts, gets diarrhea, and is off his feed for a day or two after.

    what else do i need to know other than “don’t give the dog wheat”?

  19. Shell Huber November 4, 2013 at 3:39 PM #

    Maybe the only thing that is “evolving” is the intestinal flora of the gut. I think the evolutionary process is not linear but is more branch like. Not all lineage will go so the same direction in spite of or because of environmental and dietary affects. As is pointed out in the article, few may, most won’t.
    I don’t think the intestinal flora of “most” dogs can ever evolve into mostly starch eaters because you have to factor in a natural selection of survivors passing on the genetic code to offspring who also must survive in order to become dominant. In order to be “dominant” or the “most” they must also be strong and healthy.
    This natural selection process will work given enough time with dog living without interference in starch rich environments with no other foods. The ones that do not do well on starches will have a less chance of procreating and populations will dwindle due to the lack of meats, but given enough time (thousands of years) will rebound is the food source doesn’t change again.
    This change of dogs turning into starch eaters can not happen today or the near future because the Darwinian model is not followed. Dogs procreate not because of survival or health today but because of the profit or fashion. Breeders do not select what dogs to breed based on how well they do on starches. Many good breeders will not breed very unhealthy dogs but the health issues of too much starch becomes apparent years later in health problems such as diabetes, heart disease and other starch related illness, long after the animal has left their care.
    Another way of looking at it would be to say, given enough time, children of smokers will be fine with smoking without health issues given enough time. How much time? Hundreds of years, thousands of years? But one thing is certain, until that time is reached the length and quality of life of the smokers will be less.
    Another thing is certain, my dog doesn’t have much time for his intestinal floral to change.


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