WHAT IS THE TRUTH ABOUT RAW FOOD DIETS?
There is currently a lot of interest in feeding dog and cat diets made of raw ingredients.  The theory behind this trend is that wild animals eat raw diets, so they are presumably adapted to uncooked, unprocessed foods.  There is an element of truth in this idea, but scientific studies tell us there are also cautions for anyone considering raw foods for their dogs.

What do dogs and cats eat in the wild?
Dogs eat a variety of foods.  Studies in wild canids show that 1/3 of their stomach contents consist of plant material, and they eat and digest grains, fruits, and vegetables in addition to prey that they catch.  When a dog, coyote, or fox catches a rabbit, the first part eaten is the "entrails"--intestines, liver, and other internal organs, followed by the muscle tissue (meat).  Presumably the intestinal contents are eaten along with the rest, giving the dog some pre-digested plant material in the diet.
Cats are true carnivores, eating only prey that they eat.  They often eat the entire mouse or bird.  Cats also are known to eat grass, but it is thought that they do not do it for nutritional reasons.

What about commercial dog and cat foods?  For economic reasons, carbohydrates (from grains) are used to supply energy.  Even though dogs in the wild do not get a large portion of their energy from carbohydrates (and cats get little or none), normal dogs and cats can use carbs as part of a balanced diet, allowing the protein in the diet to be used for vital tissue building instead of being burned for energy.  Commercial foods are usually much lower in protein than the natural diets of dogs and cats; in most cases this is economical and provides good nutrition.

What are the claims of raw food diets?  In addition to being more "natural" (although is is doubtful that these diets actually look very much like the ancestral diets of our pets), these diets claim that they contain enzymes that help the animal get the most nutrition from the food.  Since these claims actually refer to cellular enzymes in the raw ingredients (all cells contain a variety of enzymes that are part of the cell's machinery), not digestive enzymes, there is no evidence that these enzymes have any beneficial effect.  Since enzymes are made up of proteins, any enzymes found in the food are destroyed by the digestive process, so they are not absorbed by the body.  Another claim is that vitamins are destroyed by the cooking process, which is true.  This is why commercial pet foods spray vitamins and essential fatty acids on the surface of the foods AFTER cooking, so that these nutrients are not destroyed.  Some raw diets also claim that they contain helpful bacteria that aid the animal in some way.  While it is true that cultures of certain normal digestive bacteria (such as Lactobaccillus, found in live-culture yogurt) have a beneficial effect in the intestine, the bacteria found in raw diets are usually other types of microorganisms that have not been shown to be helpful.

What are the problems with raw diets?  There are two concerns.  Nutritional studies of commercially produced raw diets have shown that they are not nutritionally adequate and balanced by any normal standards.  Some proponents of raw diets claim that the diets cannot be tested, because they feed different foods in different meals, but even when all the meals are added together they are not a balanced diet. The second concern is that home-prepared raw diets studied often contained known food-borne diseases, including Salmonella, E coli, Campylobacter, and other potentially serious infections.  We do see dogs and cats that are ill with fever and intestinal symptoms after eating raw diets, and it is likely that these are "food borne illnesses".

What is true about raw diets?  Some cats seem to be "carbohydrate intolerant", and gain weight and become diabetic on commercial dry food diets.  These cats would do better on diets with minimal carbohydrates, whether raw or cooked.  We recommend commercial canned kitten food for these cats, which helps control weight and lower blood sugar.
Some dogs and cats with intestinal problems or skin problems seem to do better on these "natural" diets.  This is likely NOT due to the diet being raw, but rather may be that there are fewer ingredients (with less chance that the diet will include some ingredient to which the pet is allergic) or higher protein levels.  In an interesting twist, it has been found that some dogs with skin allergies are actually allergic to the microscopic grain mites that are commonly found in dry dog foods.  Some of these allergies resolve when the dog is fed a canned foodmoist diet (raw or canned), even if the food ingredients are exactly the same.

What should we feed?  The scientific evidence makes it difficult to suggest feeding raw food diets, but many of the potential benefits can be obtained by choosing commercial foods carefully.  We increasingly suggest canned food diets for cats, especially when the cats are overweight, diabetic, have intestinal problems, or have bladder disease.  Dogs with skin problems often benefit from "food allergy" diets that use a limited number of pure ingredients to eliminate potential allergy-causing components of the food.  For most pets, however, the safest and most nutritious diet will be one of the high-quality premium diets.

This subject is one of great controversy and high emotion.  We encourage our clients to ask questions if you would like to more about your pet's nutrition.