by Marion Nestle
Mar 28 2013

Yes, dogs can eat carbohydrates, and here’s why

When Mal Nesheim and I were writing our book about the pet food industry, Feed Your Pet Right, we were constantly challenged to defend our contention that dogs can eat pretty much anything, including commercial food products made with grains.

Our reasoning: dogs are not wolves.  They evolved to take full advantage of the leftovers from human food consumption.

Now a study published in Nature Magazine, “The genomic signature of dog domestication reveals adaptation to a starch-rich diet,” explains how this happened. 

The investigators sequenced the entire genomes of dogs and wolves.  They identified 3.8 million genetic variants, and used them to identify 36 genomic regions that appeared related to dog domestication.  Many of these gene regions appear to be associated with the behavioral changes needed to domesticate wolves.  

Ten of the genes turned out to have roles in starch digestion; three of these genes promote digestion.

The investigators identified mutations in key wolf genes that allowed this to happen.  The study provides evidence that dogs “thrive on a diet rich in starch, relative to the carnivorous diet of wolves.”  

This, they say, constitutes a crucial step in the early domestication of dogs.

In conclusion, we have presented evidence that dog domestication was accompanied by selection at three genes with key roles in starch digestion: AMY2BMGAM and SGLT1. Our results show that adaptations that allowed 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 early dog domestication…In light of previous results describing the timing and location of dog domestication, our findings may suggest that the development of agriculture catalysed the domestication of dogs.

 If your dog is domesticated, it will love those carbs just as you do.  But keep it away from the pizza and cookies.  We seem to have co-evolved to put on the pounds together too.

  • Mary

    People are developing very strange and unscientific ideas because of the food hysteria that has been created in our culture. I thought this bit from Maryn McKenna the other day was nice evidence:

    @marynmck: Signs of a society w a food pathology, No. 2: gluten-free grass. for pets.

    Some of the fears that have been generated are probably worse for people’s stress levels than just letting their dog have carbs or their cats have gluten.

  • brad

    I wonder if the same evolutionary adaptation can be detected in humans, which would knock down one of the foundational arguments of the paleo crowd, who argue that humans aren’t supposed to eat grains because they weren’t part of our ancestral diet?

    I used to share a house with two anthropologists who were among the world’s leading experts on prehistoric diet, and they always shook their heads in confusion over people who advocated the paleo diet. For one thing, it was clear to them that humans evolved as opportunistic omnivores, but the main issue is that they couldn’t understand why anyone would want to mimic the diets of people who had a life expectancy of 30-40 years. It’s not that they thought the diets were killing them off, it’s that our distant ancestors didn’t live long enough to develop the late-in-life diseases that may be caused by diets high in red meat and saturated fat. So we don’t know if those diets are actually healthy over the long term; the paleo people are running that experiment on themselves, and until we have a few tens of thousands of them in their 80s and 90s who’ve followed a paleo diet for 40 years or more we won’t really know the answers.

  • Hi Marion,

    This is an interesting discussion. I wouldn’t be surprised to know that dogs can take carbs like man because I always see my neighbour’s dog gobbling up all the rice. 🙂


  • We feed our two pugs a raw meat and bones diet, with some occasional small amounts of fruit. No grains. Starch only when they have diarrhea – sweet potatoes usually fix that up right away.

    They are the leanest/fittest and healthiest pugs you will ever see. Both are about five years old, they never get sick, and we only visit the vet when its time for shots.

    Don’t think we’ll be changing their diet anytime soon.

  • TJ

    The study’s (and your) implication that dogs can “thrive” on starch is a strange one. Who is defining “thrive”? Survive, sure, that’s what genetic adaptations are for, but thrive? That’s a stretch. You are reducing the complexity of way too many issues, like hormone regulation, satiety signals, and ideal micronutrient intake for dogs. Of course, everybody does this with humans too when they say “it’s all about calories” so I guess this isn’t surprising.

    @brad there is plenty of documentation of hunter-gatherer societies with longevity similar to ours. See:

    Or check out the mid-Victorian period:

  • B.

    The latest research being done is investigating the link between grains, namely corn, and an increase in cancer in dogs. Corn is the most heavily sprayed food corp. This includes pesticides and herbicides.

  • brad

    @TJ: Thanks — in fact the Victorian diet appears to have been high in whole grains, according to the article you linked to.

  • TJ

    @brad: Yup. Make sure you also eat your fruits, roots, vegetables, meats, organ meats, fish, nuts, legumes, and eggs. Minimal refined sugar, refined grains, and no processed foods – and get lots of exercise.

    Basically a “Paleo” diet with whole grain “cheats”.

    And hey, look at that, no calorie-counting.

  • Pat McClure

    my wife cooks meat for her precious baby (aka dog). Insanity? That is what I think too.

  • Laura Collins

    Wow, this is so interesting.

  • Like the article. I have always fed my 2 cocker spaniels high protein gluten free kibble but with a large percentage of carbohydrates in the form of rice. They are healthy well balanced dogs. Also – if ever poorly, they get boiled chicken and lots of boiled rice – they love it.
    Guess it is about being sensible about what sort of carbs and how much you give your dog as to whether good for them or not?

  • pup

    ‘Thrive’, in the scientific sense, simply means to survive and reproduce. Humans can ‘thrive’ on a diet of pizza and mountain dew; and if, as we’ve done with dogs for tens of thousands of years, we were to carry out an intensive eugenics program based around that diet, we’d end up with humans who were better adapted at thriving on pizza and mountain dew. That’s how the evolution do. That of course doesn’t mean that we should eat every meal at pizza hut, only that we can.

    So, +10 points for the rather obvious headline. -20 for the rather ingenuous argument that follows.

  • Janknitz

    Certainly dogs CAN eat carbohydrates, but SHOULD they?

    In particular, should they be eating hybridized and/or GMO grains, because those now make up a huge percentage of dog food? Do dogs really have the genes to process these frankenfoods any more than the growing number of humans suffering from celiac disease, gluten intolerance, and auto-immune disorders as a result of gut dysbiosis from the pytates and proteins in these grains???

  • brainmatters


    The paleo crowd is wrong from the get go. Early humans consumed plenty of grain. They were primarily gatherers, not hunters. Meat was only scavenged and not regularly available. Diets varied greatly throughout time and place and humans survived–and thrived–by being able to eats lots of things, kind of like our canine friends.

    If you go back to Australopithecus, it was a completely vegetarian species. Meat likely became important in brain development, but it was not the basis of the diet. People ate native grasses (the precursors to modern grannies) –where do these “paleos” think people got the idea for agriculture?

  • Interesting, since dogs can consume carbs, obviously they are susceptible to diabetes, obesity and all other carbs related illnesses. I should better be careful with my dog’s diet.

  • Why assume that genes for digestion of starch have anything to do with the metabolism of gluten? Or indeed, why assume that metabolism of glucose improves just because its digestion does?
    What if this was an adaptation to improve exploitation of starch when it was available in diet in SMALL amounts or in hard-to-digest foods?
    Humans have many more copies of these genes than dogs but many cannot cope with cereal proteins and many more cannot tolerate diets where carbohydrate outweighs fat.

    My dogs vet said “be sure to give your dog dried chow”. a minute later he said “You can expect your dog to suffer from cancer and arthritis when it’s mature”. I made the connection even if he didn’t, because I’d already cired my arthritis by avoiding grains and reducing carbohydrates.

  • @ brainmatters,

    plainly dog’s ancestors were not hunters but gatherers who ran around collecting grains. This is why dogs still eat grass when they’re sick. Sure they dug up the odd bone, but that was so they could make gravy with all the flour they milled.

  • simba

    Why is it people get so worried about diseases supposedly from dog food, and much less so about diseases proven to be genetic? Or, hell, about obesity?

    Anectdotal evidence- some friends for years had dogs who were fed mainly off potatoes, bread, table scraps, and kibble. Said dogs lived to 15-17 easily (unless killed in accidents), because they were small, tough members of long-lived breeds who were well-exercised and kept thin. They couldn’t believe it when I mentioned a 12 year old dog as being ‘old’, because he was only hitting his prime then. And most 12 year old dogs of long-lived breeds won’t look ‘old’, if kept at the right weight.

    Traditional diet for working sheepdogs in many areas was oatmeal with fish meal or milk. There isn’t exactly a concomitant tradition of obese sheepdogs, because they were given an appropriate amount of food and lots of exercise.

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  • This post of yours is really a potent forum to support what we have taught about dogs when we were kids–that dogs are omnivores (as you mentioned, they’re not wolves.) I also loved when I heard about the starch digestion in dogs. At least, dog owners would love to have a wider range of alternatives outside the usual dog foods.

  • Like the common folks’ rumors, it seemed like there’s a lot of do’s and dont’s for these canine individuals in terms to food selections, just like not to be feeding chocolates because it turns out to be a poison in disguise. Anyway, thanks at least for making it clear and adamant that dogs are really friendly with carbs. Now I can be totally at least feeding some good carbs on them. 🙂

  • This is the nice evidence for people to let them know about the dogs can consume the leftover food of humans.There isn’t any hindrance for human to give their food to dogs.

  • I am very glad to read that our leftover food can be consumed by our dogs. As they love the food which is rich in starch and they can have any commerical food.

  • Carbohydrates play a vital role in humans daily life. I m astonished to hear that dogs can also have the same food as human have, that can be rich in carbohydrates.

  • Pet food was an extra expenditure for me before reading this paragraph. I am very happy now that I don’t have to buy a pet food, now I can manage my pet’s food from our daily diet.

  • Amity Allcock

    Make sure you supplement with calcium. It is crucial that dogs get enough calcium in their diets and with home-cooked food that can be difficult.

  • Teresa Garcia

    Life expectancy is an AVERAGE and it includes infant mortality. So if two infants, age 1, die per each human who lived to be 80, the life expectancy would be…..27! The “life expectancy” of early humans was drastically skewed by the number of children who didn’t survive infancy, rather than by the actual life span of those who did survive infancy.