Parabacteroides distasonis, Parabacteroides goldsteinii, and Parabacteroides merdae have been shown to reduce obesity in vitro and in mice by regulating SCFAs, bile acids, AMP-activated protein kinase (AMPK), G protein-coupled bile acid receptor 1 (TGR5), farnesoid X receptor (FXR) pathways, and the mTORC1 pathway. Here, GPBAR1 is linked to obesity due to melanocortin 4 receptor deficiency.