study done on Labrador retrievers that found a gene alteration that correlates with greater food-motivated behavior. This gene alteration can also be linked to canine obesity. Scientists were curious as to why there seemed to be more obesity and food interest in Labs compared to other breeds. They took a small sample size at first of obese and lean Labs and studied three obesity-related genes. In the majority of the obese dogs, they found a variation in one of the genes that is responsible for turning hunger "on" and off." The dogs with this variation tended to have more food obsessed behaviors. They begged more than non-affected dogs and were overall more interested in food and continuing to eat even after meals.
The most interesting finding of the study however was that this variation was found more commonly in assistance Labs. This finding is surprising, but makes sense because assistance dogs are trained with food rewards. If the dog is genetically predisposed to being more food-motivated, than it is more likely to be selected as an assistance dog because it is easier to train.
Pavlov might have just had an obese Labrador retriever.