Halliday TM, Rynders CA, Thomas E, et al. - The present study sought to investigate appetite-related hormonal and behavioral responses to short-term overfeeding (OF) in adults classified as obesity prone (OP) and obesity resistant (OR) and ascertain if acute responses were correlated with long-term weight gain. For this investigation, OP (n = 22) and OR (n = 30) adults ate a controlled eucaloric and OF diet (140% of energy needs) for 3 days, followed by 3 days of ad libitum feeding. By visual analog scales, hunger and satiety were assessed. During a 24-hour inpatient visit on day 3, ghrelin and peptide YY (PYY) levels were measured. According to results, dietary restraint and disinhibition were higher in OP compared with OR candidates, and disinhibition was linked to the longitudinal weight change. Energy intake fell significantly in OR candidates following OF but not in OP candidates compared with the eucaloric diet. Baseline disinhibition and PYY responses to OF varied between OP and OR adults. Appetite regulatory variations can underlie differences in weight gain propensity.