Obesity is on the rise in dogs. 40% of dogs are obese and that number is slowly climbing. Obesity is a very serious condition and is defined as weight more than 20% of the ideal body weight. Dogs usually become obese from a more sedentary lifestyle and receiving more calories than needed. There are a few diseases that can cause obesity in dogs, hypothyroidism and Cushing’s disease are two of those, so testing before going on an weight loss program is recommended.