In addition to regulating the gut microbiota, these primary and secondary BAs influence the pathogenesis of metabolic diseases including NAFLD, T2D, and obesity by regulating receptors, including farnesoid X receptor (FXR) and Takeda G protein-coupled receptor 5 (TGR5) [9–12]. This evidence concerns the gene GPBAR1 and obesity due to melanocortin 4 receptor deficiency.