Weight loss outcomes are generally worse for dogs and cats with class II obesity, defined as >40% overweight

Abstract

In pet dogs and cats, adiposity is usually estimated clinically using a 9-point body condition score (BCS), with BCS 9 equating to 40% overweight. Animals that are > 40% overweight are not depicted, but it is unclear both how prevalent they are and whether being > 40% overweight affects weight loss outcomes. Records of dogs and cats attending a specialist obesity care clinic, where adiposity is instead determined using dual-energy X-ray absorptiometry, were reviewed. Animals were assigned to two classes (class I ≤ 40% overweight: 118/398 [40%] dogs and 68/116 [59%] cats; class II, > 40% overweight: 180/398 [60%] dogs and 48/116 [41%] cats) and weight loss outcomes assessed. Compared with class I, fewer class II obesity dogs completed weight management (P < 0.001), rate of weight loss was slower (P = 0.012) and lean tissue loss was greater (P < 0.001). Cats with class II obesity lost more weight (P = 0.048) albeit over a longer period (P = 0.043), and also lost more lean tissue (P = 0.004) than cats in class I. Approximately half the pets presenting to a specialist clinic were > 40% overweight and are, therefore, not well depicted using the current 9-point BCS. Weight loss outcomes are generally worse for animals with class II obesity than those with class I obesity.