Vertical sleeve gastrectomy in adolescents reduces the appetitive reward value of a sweet and fatty reinforcer in a progressive ratio task

Abstract

Background: Adolescent obesity is challenging to treat even if good multidisciplinary approaches are started early. Vertical sleeve gastrectomy (VSG) is an effective intervention for long-term weight loss, but the underlying mechanisms that result in reduced calorie intake are controversial. Anecdotal evidence from the clinic and evidence in rodents after VSG suggest a decrease in the reward value of high-calorie dense foods. Objectives: To determine changes in appetitive behavior of candies (high in sugar and fat) after VSG in adolescents with obesity. Setting: University hospital. Methods: Sixteen adolescents with obesity (age 15.3 ±.5 yr) who had VSG and 10 control patients (age 13.8 ±.6 yr) who had not undergone surgery were studied. Both groups completed a progressive ratio task by clicking a computer mouse on a progressive ratio schedule to receive a candy high in sugar and fat. In the task, patients were required to expend an increasing amount of effort to obtain the reinforcer until they reach a breakpoint (measure of the reward value of the reinforcer). The task was performed before VSG and 12 and 52 weeks after VSG. Results: The VSG group's bodyweight decreased from the baseline 136.6 ± 5.1 to 110.9 ± 5.2 to 87.4 ± 3.7 kg after 12 and 52 weeks, respectively (P