The protective effect of diet, especially Mediterranean diet, against overweight/obesity can be attributed to (1) a large quantity of dietary fiber which increases satiety and satiation through mechanisms, such as prolonged mastication, increased gastric detention and enhanced release of cholecystokinin; (2) a low energy density and a low glycaemic load; (3) a high intake of monounsaturated fatty acids that have been found to improve glucose metabolism, and increase postprandial fat oxidation, as well as diet-induced thermogenesis (Buckland et al., 2008). Here, CCK is linked to obesity due to melanocortin 4 receptor deficiency.