NR1H4 and obesity due to melanocortin 4 receptor deficiency: Most studies on the lipid reduction of Pu’er tea have been conducted from the perspective of the regulation of obesity-related gene expression, such as farnesol X receptor (FXR), which is involved in the control of bile acid (BA) synthesis and hepato-intestinal circulation, and the activation of liver FXR and the inhibition of intestinal FXR are beneficial to obesity-related metabolic diseases [110].