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essential nutrition advice for your pet.

What Is Grain Free Pet Food, Really?

By Lorie Huston, DVM


Grain free pet foods are currently very popular. But are they really healthier for your pet than other types of pet foods? Let’s take a closer look at that question.


While it is true that many pets do well on grain free diets, it is also true that these diets were developed more in response to consumer (i.e., human) preference than to the actual nutritional needs of our pets.


Nutritionally, the most important aspect of a pet food is whether the food provides complete and balanced nutrition. If the food contains excesses or deficiencies of specific nutrients, the pet will suffer as a result. This concept is true regardless of whether the food contains grains or not.


Each ingredient in the diet provides a unique set of nutrients to the overall makeup of the food. Together, the ingredients need to combine to provide a complete nutrient profile for your pet, without any excesses or deficiencies that can cause illness for your pet. It is certainly possible for grain free diets to provide this type of complete nutrition for your pet. However, these diets are not the only option, or even necessarily the best option, for each individual pet. There is no one diet or type of diet that is perfect for all pets. In other words, no pet food is a one-size-fits-all nutritional solution.


Does Grain Free Mean Carb Free?


Another popular feeding concept that often seems to go hand in hand with feeding grain free pet food is the feeding of a high protein, low carbohydrate diet. High protein, low carbohydrate diets do have their place, particularly in the feeding of diabetic cats. However, it is important not to assume that a grain free diet is a low carbohydrate diet. In fact, some grain free pet foods contain carbohydrate levels similar to or even higher than diets containing grains. In many grain free diets, ingredients such as potatoes replace the grains in the food and often these ingredients have more carbohydrates than the common grains used in pet food. As a result, grain free and low carbohydrate pet foods are not always synonymous with one another.


Is Grain Free Pet Food More 'Natural'?


Proponents of grain free diets sometimes claim that grains are an unnatural source of nutrition for our pets. They argue that ancestors of our current-day dogs and cats did not eat grains. However, it could be argued that potatoes and other forms of carbohydrates are no more “natural” for our pets than are grains. Fortunately, our pets (dogs and cats alike) have evolved to be able to digest grains as well as many other sources of carbohydrates (including potatoes).


What About Cat and Dog Food Allergies?


Another popular misconception that many pet owners fall victim to is the assumption that grain free diets are the best diets for pets with food allergies. While food allergies do occur in pets, corn and other grains are not among the most common allergens found in foods. In fact, according to some of the available research, corn is actually one of the least likely sources of food allergy. In one literature review1, 278 dogs with food allergy were evaluated and the problem ingredient was clearly identified for each dog. Beef was the most common allergen, being responsible for 95 of the cases reported. Dairy was responsible for 55 cases, making it the second most frequent cause. Corn was identified as the offender in only 7 cases. In cats, the situation is similar. Fifty-six cats were evaluated in this study2. Forty-five of the food allergies resulted from eating beef, dairy, and/or fish. Corn, meanwhile, was responsible for only 4 cases.


Feeding a grain free diet is a legitimate option for your pet. However, feeding a grain free diet still requires choosing a diet that includes complete and balanced nutrition for your pet. Choose ingredients with which you, as a pet owner, are comfortable. But remember that in the long run, it is the nutrient profile that is important, not the individual ingredients in the pet food.


As with all things related to your pet’s health, your veterinarian is your best source of information regarding pet foods. Your veterinarian is knowledgeable about all types of pet food and can help you determine the type of diet that is best for your pet.


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Chesney CJ. Food sensitivity in the dog: a quantitative study. J Sm Anim Pract 2002;43:203-207.

Elwood CM, Rutgers HC, Batt RM. Gastroscopic food sensitivity testing in 17 dogs. J Sm Anim Pract 1994;35:199-203.

Harvey RG. Food allergy and dietary intolerance in dogs: a report of 25 cases. J Sm Anim Pract 1993;34:175-179.

Ishida R, Masuda K, Sakaguchi M, et al. Antigen-specific histamine release in dogs with food hypersensitivity. J Vet Med Sci 2003;65:435-438.

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2 Carlotti DN, Remy I, Prost C. Food allergy in dogs and cats. A review and report of 43 cases. Vet Dermatol 1990;1:55-62.

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Comments  6

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  • Grain-free is better.
    09/14/2014 01:33am

    You ask: " But are [grain-free pet foods] really healthier for your pet than other types of pet foods? " --- The short answer is "YES". Grains are highly inflammatory, and inflammation in a dog's body leads to heart disorders and cancers. The current crops of hybrid grains, particularly wheat and corn, also are converted into sugar in the blood faster than candy bars. Engineered grains are designed to survive pesticide and weed killer sprayings, but the harmful ingredients of those sprays persist in the grains. Canines are carnivores with digestive systems not intended to survive on grains. They do not provide all of the amino acids which dogs need and meats provide. Dogs have short digestive systems, and grain proteins are far less digestible than meat proteins.

    I do not understand why you persist in falling for the commercial dog food industry's self-serving effort to humanize pets by feeding them human foods, like grains, rather than their natural diet of animal proteins.

  • 01/19/2015 03:51pm

    Great explanation of the benefits of grain-free dog food, rodrussell! I was a bit skeptical at first myself but I'm now a converted believer. I buy my grain-free dog food at http://buygrainfreedogfood.com/

  • 06/19/2015 03:46am

    rodrussell, I believe you might be conflating a few issues. There is a huge difference between feeding your pet a food with grains and feeding him some crap where the first ingredient is corn meal.

    Ironically the grain free foods are as the article stated more of an appeal to human trends despite your claim that it is somehow more natural for your pet. Your domesticated dog is not a wolf, and there are real problems that can occur from a diet to high in protein or fat.

    Having said that my dog has always been on grain free food, but I am trying him out on Merrick Classic recipe now that he is old enough to start running with me.

    Now as the article also stated there isn't necessarily a relationship between a food being grain free and it being lower in carbohydrates, but in the case of Merrick's recipes this is true.

    So in short for more active dogs who might need a more calories from carbs a food with high quality grains, such as brown rice, isn't necessary any worse for them than a food without any grains, and in fact could be considerably better.

  • 06/19/2015 03:39am

    Aaron S: Corn is a grain, so there really is not any difference between feeding grains and feeding corn meal. And most all grains found in dog foods are nothing like the grains of 50 years ago. They have been hybridized and genetically modified to the point that they not only no longer are as nutritious -- for dogs as well as humans -- but they cause inflammation and carry pesticides which are ingested with the grains.

    I think some Merrick canned foods are excellent, like Thanksgiving Dinner and Cowboy Cookout.

  • Follow the Money
    02/10/2015 12:06am

    Rodrussel, you are entirely correct about why we shouldn't feed our dogs and cats grains. I am sure that you know why the industry continues to do. It's just yet another case of greed. Grains, especially GMO grains, are so much cheaper than meat. So, when someone buys a bag of Science Diet, priced about the same as a bag of grain-free pet food, Science diet makes a killing on their profit. Furthermore, so does the vet's office when you buy the grain food from their office. Conveniently, the vet also makes more money when your pet fails to thrive, becomes diabetic, obese, or has cancer. Also, petmd AND the author, are subsidized, directly and/or indirectly, by grain containing pet food manufactures. Of course the author wants you to believe that your vet is the best source of information about pet food. Pet owners should avail themselves to the information available on the web, or find an educated, ethical vet who cares enough about supporting your pets' OPTIMAL health and is not a shill for the grain dog/cat food industry.

  • How "Free" Is It?
    09/06/2016 09:00pm

    I want to believe in grain free foods. I mean it makes sense, when a cat/dog is in the wild they are NOT going to look for grain, they are going to look for a meat source. Wild cats and dogs eat meat, so should our pets. My cat has had urine blockages from grain in his diet. His body is NOT made to process this stuff and yet lots of pet foods put that crap in there. My vet said to switch foods so I tried Blue Buffalo Wilderness (advertising it was grain free) and after not even a full year later he got ANOTHER blockage. How actually grain free is grain free food?! I think these pet food companies are still putting something in there and labeling it as grain free. I am fed up and annoyed. What can I feed my cat without going 100% on raw diet.

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