Obesity is the No. 1 nutritional disease affecting pets today, Dr. Nancy Chilla-Smith, an associate veterinarian at PAWSitive Veterinary, says. Risk factors would include an overweight owner, whether the dogs live in a house or apartment, breed, age, and other diseases. Just like humans, “animals’metabolism slows as they age, so if the owners continue to feed them same amount the pet will gain weight,” she adds. Obesity can become a life-threatening condition. As with humans, predisposes to many diseases are diabetes, heart disease, liver disease, arthritis. But genetics do play a role and, just like with some people and ethnicities, some breeds tend to deposit fat more and have slower metabolisms.