The domestic cat, Felis catus, grows to an average length of 30 inches and an average weight of 8 to 10 pounds. When a domestic cat weighs above that range, it is possible that he is overweight.
Even a 1-pound variation from the average weight can harm a cat's health considerably. WebMD recommends three tests to determine whether a cat could be overweight. First, one can feel for the cat's ribs; if it is easy to feel them, the cat is unlikely to be overweight. Second, one can observe the cat's profile and ensure that his body is more slender from belly to hindquarters. Third, if a cat has a pouch swinging from his ribs, he is likely overweight. If one suspects that a cat is overweight, WebMD recommends taking him to the veterinarian to rule out overfeeding issues and recommend a weight loss plan.