GHRL and obesity due to melanocortin 4 receptor deficiency: Supplementation with inulin, a dietary substrate for butyrate production, determined reduction of appetite, body weight, and of the orexigenic hormone ghrelin in rats.32 Indeed, butyrate is involved in the gut-brain axis through the modulation of hormones regulating satiety and appetite signaling.33,34,35 In keeping with these findings, we found that butyrate supplementation elicited a significant reduction of ghrelin serum levels in children with obesity.