Furthermore, as well as this dysregulation of and desensitization to gut hormones in obesity, weight loss can lead to alterations in the level of secretion of some hormones, such as GLP-1 and CCK, to reduce satiety signalling and promote increased food intake, which may partly explain why weight regain is so common [109]. Here, GCG is linked to obesity due to melanocortin 4 receptor deficiency.