Is your pet overweight? I've had dogs that were a little chunky and my vet said to mix in some vegetables with their food in order to slim them down. The doctor said to add some green beans or carrots with the dry dog food for less fat, but what about the lack of protein?
Dogs can eat both plant and animal sources of protein but cats are carnivores. You can make your dog a vegetarian but it could kill your cat. Always check with your veterinarian before changing your pets diet. There are foods that give your pet the vitamins and minerals for a nutritionally balanced diet. Dr. Justin Lee explains... http://www.pethealthnetwork.com/lifestyle/it-possible-or-safe-make-your-pet-vegetarian