Just like with human obesity, canine obesity can come from a variety of causes. As an owner if your dog is becoming over weight, it is up to you to determine what the cause is. Assuming your dog has gradually begun to put on weight you should first look at any changes in environment or diet. If your dog has suddenly begun to get fat, you should seek veterinary assistance immediately as it could be a sign of more serious problems. Below are some of the most common causes of canine obesity.