For example, EGCG can exert an anti-obesity effect through the activation of AMPK, leading to the down-regulation of sterol-response element binding proteins (SREBPs) which are the transcriptional factors to up-regulate the gene expression of two lipogenic enzymes: fatty acid synthase (FASN) and 3-hydroxy-3-methyglutaryl-CoA reductase (HMGR). Here, FASN is linked to obesity due to melanocortin 4 receptor deficiency.