This is somewhat surprising given that 1) whole-body deletion of the GHSR results in reduced body weight after HFD feeding [75], 2) ghrelin deletion protects against early onset of obesity [76] and 3) rebound weight gain after diet-induced weight loss [59], although not all knockout studies have reported similar findings [77,78]. The gene discussed is GHRL; the disease is obesity due to melanocortin 4 receptor deficiency.