GRP and obesity due to melanocortin 4 receptor deficiency: Several human GWAS studies comparing non-obese and obese patients, proposed a link between polymorphisms in NMB with obesity, due to hunger disinhibition and high calorie meal preference18–20,34,35, although findings regarding the polymorphisms involved, tend to be inconsistent19,36 It is well documented that several bombesin or bombesin-like peptides are important signaling molecules in the control of weight gain and the digestive process37–39.