Food guarding is a common problem encountered by canine behaviorists. This is not surprising since canine's are predisposed to protecting their food when their ancestors needed to survive in the wild (or even from pushy litter mates). If your puppy learned to growl or snap at his litter mates in order to get any or the most food, he is simply carrying on this early learning behavior with his human family. If the owner smacks the dog for this behavior or takes the food away, this will in some cases confirm his need to guard his food. Typically, any food guarding that is challenged once the dog has possession is likely to increase his defensive behavior and become more dangerous. If your canine companion learns that aggression wins over food, he may later begin to try this tactic with other things like trophy possessions or space on his favorite couch.
The method of choice for solving this problem is to first put the behavior under stimulus control. Assuming you have taught your dog to come and sit, call your dog to you and make him sit. When he does, immediately give him a food treat and say "Take it" at the same moment. Soon a conditioned response will be established. If the dog "snaps too hard at the treat say "Gentle!" in a harsh voice and try to withhold it until the dog takes it gently. Then be sure to praise with a warm "Good". Next, begin to delay the treat a few seconds. If the dog jumps to get the treat, simply close your hand and give the instructive reprimand "Off". Soon the dog should learn that the owner has the right to control the small, quickly consumable treats. This can later be expanded to the treat being offered in the food bowl.
This method will work with dogs who have recently displayed food guarding behavior. We caution that this should not be tried with older, more serious and dominant dogs with a history of this behavior. With these dogs, you'd best consult with an animal behaviorist who can develop a safe program of behavior modification for your situation.
Courtesy of Robert DeFranco, Applied Animal Behaviorist
Executive Director Animal Behavior Center of New York
World of Dogs and Training