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Choosing the Right Diet for Your Pet

Dr De Papp

By Erika de Papp, DVM, DACVIM

Angell Internal Medicine



In our ever consumer-driven world, there is an astonishing number of pet foods available on the market today. If you watch television or peruse the internet you surely have seen numerous advertisements for grain free diets, or diets purporting to feed your dog more like the wolf from which he descended. And of course, there is no shortage of human diet fads from which to choose. But let’s be honest, many dogs and cats are pampered couch potatoes, and don’t need an ultra high protein diet suitable for dogs competing in the Iditarod! So what’s the best diet you can choose for your pet? There is no one diet that is right for every pet, but there are a few simple guidelines that can help you choose a diet, and there are many myths and misconceptions that need to be corrected. Hopefully this brief overview will be helpful to steer you down the right road.


What is AAFCO?

When choosing a commercial diet, you should always choose one that has an AAFCO statement that indicates that the diet was formulated to meet the needs of the given life stage, and that feeding trials were performed for the appropriate life stage. AAFCO is the Association of American Feed Control Officials. This organization sets the minimum standards for nutritional requirements for a complete and balanced diet for the recognized life stages; growth and reproduction, and adult maintenance. Be advised that if a food is approved for all life stages (which many of them are), this means that it meets nutrient requirements for a growing animal, and may not be the best choice for your aging dog or cat. Additionally, if you have an overweight pet, a food approved for all life stages may be too calorically dense, and not the optimal diet.


Counting Calories

shutterstock_868830Be careful when trying to look at the guaranteed analysis on the label if you are looking for certain diet characteristics. You will note that percentages are often given as minimum or maximum levels, which does not really tell you the actual percentage. Additionally, the percentages are often supplied “as fed.” When comparing canned food to dry food, the percentage of protein for instance in the dry food will look much higher because the “as fed” descriptor does not account for the water in the canned food. Moreover, most labels do not indicate calories. Not all pet foods are created equal, and one cup of Brand X does not equal one cup of Brand Y when it comes to calories. This is especially important if you are trying to get your pet to lose (or gain) weight. Just because a pet food is labelled “lite” or “for less active pets” does not mean it is calorie restricted enough. Most companies either provide calorie information on their websites, or can be contacted to obtain that information. If that information is not available then that should raise some red flags. If you are trying to get your pet to lose weight it’s best to work with your veterinarian and get specific caloric guidelines so you know exactly how much to feed. And remember, those treats can add up!


If your pet is a healthy weight and you are trying to figure out how much to feed, keep in mind that the feeding guidelines typically over-estimate what your pet needs. After all, the pet food industry is a business and they make bigger profits if they sell more food. Starting at the lowest end of the recommended feeding range on the label is a good starting point, but remember that just like people, each pet is different with respect to caloric needs, and you may need to experiment to find out what’s right for your pet.


Grain free diets

Grain free diets have become all the rage in the last few years. I suspect this has stemmed from greater recognition of gluten sensitivity in humans. Most pet food companies have jumped on the band wagon following the marketing success of grain free human diets. The truth of the matter is that there are no dog or cat studies showing a health benefit to grain free foods. A myth has been perpetuated that grains are unhealthy. In fact, whole grains contribute vitamins, minerals and essential fatty acids and are highly digestible by dogs and cats. Allergies to grains are actually very rare, and only the Irish Setter breed has been demonstrated to have a gluten sensitivity. Many grain free diets substitute potatoes and tapioca, which have less protein, more sugar, and less fiber. And typically these come at a higher cost.


Animal by-products

In addition to grain, animal by-products have become “dirty words” on the ingredient list. Although not necessarily appealing to humans (particularly in the USA), the definition of a by-product in pet food is a part of the animal that is not skeletal muscle. This includes organ meats and intestines (not intestinal contents). AAFCO specifically excludes hair, hooves, horns, hide, manure, etc… as acceptable by-products. So in reality, by-products are perfectly healthy and full of nutrients. And you can be sure that a wild wolf or mountain lion is eating “by-products” in nature.shutterstock_17569468


Raw diets

Raw diets are another popular option on the market today. Studies have shown that 20-35% of raw poultry and 80% of raw food dog diets tested contained Salmonella. This poses a health risk for your pet, but also for humans. This is especially true for children or immunocompromised adults, whether exposed to the raw food directly, or the feces of the pet eating the raw food. Additionally, there is increased risk of other bacterial infections and parasitic diseases when feeding raw diets. And the bottom line is there is no reason to believe raw food is healthier than cooked food.


The numerous dietary choices for your pet can be daunting but if you pick an AAFCO approved food made by a manufacturer with a long track record, odds are good that you will find a suitable food for your pet. Most of the large pet food companies employ full time veterinary nutritionists and have very high quality control standards. That is not to say that a small company cannot produce nutritious and high quality food, but you should check out their website if it’s a company that is not familiar to you. Take the time to research, and ask your veterinarian if you have specific questions or concerns.


Please understand that this article is meant to provide basic dietary guidelines for healthy pets. If your pet has specific health issues, then your veterinarian may make specific food recommendations, which may include special prescription diets.



For more information, please contact Angell’s Internal Medicine service at 617-541-5186 or





Freeman, Lisa DVM, PhD, DACVN; Answering Owners’ Questions About Pet Foods. 64th Convention of the CVMA, 2012.


Remillard, Rebecca PhD, DVM, DACVN; Out of the Blue Diet and Nutrition Queries. Veterinary Medicine, Sept 2015.


Carlson, Ed CVT, VTS (Nutrition); Alternative and Raw Diets – Enlightening Clients to Benefit Patients. American College of Veterinary Internal Medicine Symposium, 2015.

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