Almost half of all dogs in the United States are overweight. This is not purely a cosmetic concern. Being overweight is associated with a number of serious health concerns including diabetes mellitus, arthritis, hypertension and intervertebral disk disease. Your overweight dog is more likely to have breathing problems, an over-worked heart and an over-worked liver. Those extra pounds also increase the risk of complications if your dog has to undergo surgery, and studies suggest a correlation between bladder cancer and obesity. To top it off, your overweight dog will tend to be gassy.