In adults with obesity compared with those of healthy weight, reduced postprandial PYY secretions have been observed after a high-protein meal [8], as well as reduced suppression of ghrelin after a mixed meal [9]; by contrast, no differences in PYY and ghrelin responses after meal intake have also been reported between these groups [10]. The gene discussed is GHRL; the disease is obesity due to melanocortin 4 receptor deficiency.