Pet Food Nutrition: Grain-Free Diets

Dogs and cats are both classified in the order Carnivora. Does that mean that they should receive a strict meat-only diet? Are certain carbohydrate-sources better or worse than others? Do grain-free diets provide health benefits over those that contain grains?

Contrary to popular belief, grain-free diets do not offer health benefits over diets than contain grains. Dogs are actually considered omnivores (and thus more similar to bears, skunks and racoons), and both dogs and cats have the ability to digest, utilize and benefit from a nutritionally balanced diet containing carbohydrates, including grains. In fact, animals do not treat grains differently from other sources of carbohydrates like potato and apple – the body recognizes the food by the nutrients it provides, not by its source. The starch (the main carbohydrate) in grains is actually highly digestible for both dogs and cats – 95% or higher.

Many manufacturers, in an attempt to make their diet stand out in a competitive market, advertise grain-free diets as being healthier, when in reality they are readily comparable to their grain-containing counterparts. Many grain-free diets are not actually lower in carbohydrates, but rather use alternative sources of carbohydrates, such as potatoes and tapioca, which are actually lower in protein and higher in sugars than grains.

So what other benefits do grain-free diets claim? Some claim that the risk of food allergies, obesity or diabetes is higher in diets that contain grains as the source of carbohydrates. True food allergies (reaction of the immune system to certain food proteins) are actually quite rare but can be caused by any ingredient that has protein. Food intolerances (which don’t involve the immune system) are usually in response to certain nutrient profiles, such as high-fat diets, and are rarely related to grains specifically. The most common allergies in dogs are beef, dairy, wheat, chicken and egg; in cats beef, dairy and fish are most common. Usually animal proteins are more common causes of allergies than grains or other carbohydrate sources. However, if an animal is truly allergic to a single type of grain (for example, wheat), feeding other types of grains (like oats and rice) should not be a problem.

Obesity is a serious disease that affects a large number of our animal friends. However, the main cause in both dogs and cats is excessive calories – regardless of the source. Many grain-free diets are actually higher in calories and fat; they can be easy to over-feed and the fat makes them very palatable. Regardless of the type of diet fed, owners should monitor their pet’s body condition and weight carefully and feed accordingly.

Diabetes in dogs is related to the destruction of specific cells in the pancreas, and cannot be induced with diet. However, it has been shown that achieving and maintaining optimal weight and providing a consistent diet and meal times can help in managing the disease in dogs. Cats, on the other hand, are prone to developing diabetes if their weight is not-well managed. As mentioned above, diets containing grains do not promote obesity. While some research has shown that diets with lower carbohydrate content can be useful in managing diabetes in cats, most of these diets contain grains.

While grain-free diets can provide excellent nutrition, they do not offer health benefits over diets than contain grains. It is important to assess your pet’s diet based on overall nutrient profile rather than individual ingredients, and to not be swayed by marketing tactics.

Vanessa Tonn, DVM

Bowmanville Veterinary Clinic