By Dr. Sarah Sullivan Nutrition is a critical part of our health, and is no different for our pets. It's also an area of intense discussion and growing controversy. Clients ask me everyday what food they should feed, and inevitably our discussion ends up covering several sensitive topics. Often dog owners have read information online, discussed the topic with fellow owners at the park, and spoken with pet store staff regarding options. They may even have received conflicting advice from a previous veterinarian. I'll try to shed a little light on what choices are available, to help you make a better informed decision. As with any nutrition advice, I would recommend you discuss your decision with your dog's veterinarian before implementing any changes. Diets generally fall into one of the following categories, with a few crossover exceptions: Home-cooked: This encompassed almost all diets until the 1970s and 1980s, when commercial pet foods became more popular. Until that time, there were a handful of common diseases caused by nutritional deficiencies in home prepared diets. These diseases became extremely rare as most owners began feeding complete and balanced prepared diets. With the resurgence of home-cooked diets over the last 10 years, we are beginning to see these diseases again. If you are interested in preparing your dog's food at home, there are some excellent resources to make sure your dog isn't missing any critical nutrients. I often suggest clients schedule a phone consultation with Cornell Veterinary School's nutrition team. They are some of the leading veterinary nutritionists in the country, and offer a reasonably priced service to help you formulate an individualized diet. Speak to your vet about this option and they can help you make an appointment. Raw diets: The popularity of these diets rose in the 1990s and early 2000s, partially with endorsements from many breeders pushing the BARF (bones and raw food) approach to nutrition. As science has caught up with this trend, a few concerns have emerged--I'll outline them here just to make sure you are aware of them. Primarily, studies are showing that dogs on a raw food diet shed Salmonella bacteria in sufficient quantities to infect humans and other dogs around them. For this reason, dogs on a raw food diet should not be around infants, elderly individuals, or anyone who is immunosuppressed. As a result, many therapy dog programs do not allow dogs on raw diets to participate. Additionally, many academic veterinary hospitals will not admit patients on raw diets due to the risk to their staff and other patients. It takes seven days after a raw diet is discontinued for this shedding to resolve. If you are worried about the risk to yourself or a family member, I would strongly recommend you speak with your own doctor. Also, unlike wolves, dogs are a species that was domesticated by eating the scraps from human meals. They are not intended to eat only raw, freshly killed meat. Prescription diets: These foods are available under the supervision of a veterinarian, and should be fed as directed. These diets are used as a critical part in management of kidney and bladder stones, chronic pancreatitis, allergies, liver failure, heart disease, and a growing list of other conditions. If your vet has prescribed a specific food, be sure you speak with him or her and understand exactly which diet(s) are acceptable, and which are not. This will include everything your pet eats, from the food itself to treats, table food, and edible toys (rawhides, bully sticks, and toy stuffings are some of the most common non-compliant offenders). Commercial diets: This is the largest category, and the one you probably wanted to know about in the first place! Over the last 10 years this group has grown exponentially, and often follows trends in human diet fads. I'll define a few things that should help you navigate your choice in this category. 1. The AAFCO statement is a fine-print sentence usually found on an unobtrusive part of the bag/can, and is probably the single most important thing in evaluating a diet. AAFCO is the organization that regulates pet food packaging, and they maintain strict standards (based on the best science available) for what is considered a well-balanced, complete diet. A complete diet includes all the macro and micronutrients your dog needs to be healthy, in an appropriate ratio. The statement should say something along the lines of "This food has been formulated according to / has been approved by AAFCO standards as a complete and balanced diet", either for "growth and maintenance", "maintenance", or "all life stages". If this statement is not on the bag, it is a very fancy dog treat and is missing some critical nutrients. 2. The ingredient list is in order of weight at the time of addition to the mix, meaning that any dehydrated ingredients will be listed later than those with high water contents. This often upsets owners, because the feel that an "undesired" ingredient is making up the majority of the food. In reality, the order of the list means little without context. 3. Organic and natural are two terms that are NOT defined or regulated in the pet food industry. This means that if you are committed to feeding your dog food that is up to human-grade organic standards, you are going to have to do some serious research into the company and food you are looking at. Be aware that different formulas and even different flavors will have dramatically different preparations and that even within one labeled food, the company has some wiggle room in what they include from batch to batch. 4. Protein sources used to be limited to basic meats like chicken, beef, and pork. More 'exotic' protein sources were reserved for animals on prescription foods for either food intolerances or true food allergies. The recent trend in commercial diets has made these proteins--salmon, venison, bison, rabbit, and even koala--more easily found. Really, it doesn't matter what protein you feed, as long as the diet is balanced and nutritionally complete. However, be aware that if your dog does have a true allergy, you should be feeding a single protein, not multiple ones, and you should not be switching between them. Dogs can only develop allergies to things they have been exposed to, so exposing your dog to a large variety of proteins or switching between them frequently may limit what foods are options in the future. Generally, I recommend people select one food that their pet does well on, and feed that long term. 5. Carbohydrate source is the current hot topic in pet food. Everyday I have a handful of clients ask me about 'grain free' foods, and a growing number of my patients are on these diets. This trend is closely following the same one in human diets, and is not based on any new consensus in veterinary nutrition science. There are some animals who seem to do well on a grain free diet, and some that do not tolerate corn very well, but they are the exception to the rule. Most true food allergies in dogs are protein-related, and even then are relatively rare. Nutritionally I don't have a preference on source, as long as there are plenty of carbohydrates in the diet (dogs aren't carnivores--they need carbs!). I do see a fair number of dogs with loose stool or intermittent diarrhea on grain free diets, however. Some of these diets contain richer ingredients in general, and some dogs do better on a blander diet. 6. "Byproducts" has become a bad word when discussing pet food, but it includes lots of excellent cuts of non-muscle meat. Often these parts of the animal are more nutritionally rich than what we think of as the "prime" cuts. Ultimately, your food selection should be based on your pet—his/her health and nutrition requirements. Make sure you are feeding a complete and balanced diet (either assured by the AAFCO statement or a veterinary nutritionist) that is approved by your veterinarian. Make sure it is appropriate to your dog's life stage (e.g. puppy, adult, or senior), and try not to switch between foods more often than absolutely necessary.