Given the importance of digestive efficiency to health and disease, and the proven utility of targeting digestive efficiency to treat obesity (e.g. – orlistat), we hypothesize that further investigations into mechanisms (such as the RAS and its AT2 receptor) that control digestive efficiency may lead to the development of more efficacious anti-obesity therapeutics. The gene discussed is AGTR2; the disease is obesity due to melanocortin 4 receptor deficiency.