NR1H4 and type 2 diabetes mellitus: Serum bile acid was found to increase after bypass surgery but not in LAGB, and the increase was correlated with weight loss.107 Recent experiments on gene kick‐out mice demonstrated that bile acid, not GLP‐1, was the key player in SG.108 Therefore, bile acid, through the nuclear farnesoid X receptor (FXR) in liver and small intestine, may play very important roles in weight reduction and T2DM remission.109