A variety of genetic and environmental factors that confluence since the 1980s account for the increased prevalence of obesity.(36, 41) Leptin’s role in regulating food intake and energy expenditure has been identified as a component of the pathophysiological alterations of obesity, including hyperinsulinemia and its complications.(42) Many other orexicans and anorexicans are now known to influence the regulation of food intake.(16, 30, 43) However, prevention is critical, since effective treatment of this disease is limited. Here, LEP is linked to obesity due to melanocortin 4 receptor deficiency.