In recent years, TGR5 signaling, which is activated by bile acid, has gained much attention as a key mechanism for regulating glucose metabolism and energy expenditure, and their interaction was found to protect against hyperglycemia, diabetes, and obesity; in addition, it was also found that signaling by bile acids can occur through TGR5 in the intestine [46]. This evidence concerns the gene GPBAR1 and obesity due to melanocortin 4 receptor deficiency.