SIRT1 also regulates the activity of various metabolic transcription factors, including peroxisome proliferator-activated receptor γ (PPARγ), liver X receptor (LXR), and farnesoid X receptor (FXR), which in turn affect lipid metabolism and insulin sensitivity, demonstrating its role in controlling obesity and related metabolic disorders [124]. This evidence concerns the gene SIRT1 and obesity due to melanocortin 4 receptor deficiency.