While it can and is argued by many that, for people, a vegetarian diet is more healthful, and probably more like the diets of people hundreds of years ago, the same cannot be said of dogs. Dogs are omnivores, and opportunistic eaters. Wild dogs may snack on rodents, small birds and reptiles. As a result, dog food of any kind is not exactly “natural” in terms of what a dog would eat in the wild. Many vegetarian dog foods do not supply all of the nutrition that the animal needs, but it may be possible to supplement the food to make sure that the diet is healthy.
When dogs eat dog food, the most important component is making sure that the food meets safety standards, according to Pettable. The primary agency that addresses this in the US is the Association of American Feed Control Officials (AAFCO), and any pet food that you give your dog should be AAFCO certified in order to meet its health needs. Further, studies on dogs that have been fed a vegetarian diet show that they often do not get all of the nutrients that they need.
It may be possible to supplement vegetarian dog food with the appropriate vitamin and minerals so that the animal’s diet is balanced. This should be done under supervision of a veterinarian. After switching a dog to vegetarian food, you should have the dog examined one to two months later to have general health evaluated.
Signs that a dog may not be tolerating vegetarian food well include vomiting or diarrhea, hair loss, loss of energy, or merely appearing “off-color.” One of the most common replacements for the protein provided by meat in most dog foods is soy. Some dogs, like some people, do not tolerate soy well.
Further problems with vegetarian dog food may be encountered if the dog food contains no animal products — like eggs, for example — and is completely vegan. While some dogs can do very well with vegetarian food, many dogs do not respond well to a completely vegan diet. It is very challenging, even with supplements, to completely meet a dog’s nutritional requirements with vegan food.
Some dogs will not respond well to vegetarian dog food, even when it does contain animal products, so you should accept that you might ultimately have to feed the dog a meat-based food. If this is unacceptable for personal reasons, you may be better off not adopting a dog unless the animal has had proven success with a vegetarian diet.
If you would like to switch a dog to vegetarian food, only purchase food that has been tested and meets all nutritional standards for dogs. There are many brands that offer this certification, and you can find the most variety at feed stores or at large pet stores. There are also books devoted to making vegetarian foods for your dog, and some of these recipes may also meet AAFCO standards.