In our previous study, we demonstrated that, besides obesity, fasting also represses CYP2R1 in the liver, which involved potentially both the GR and PGC‐1α‐ERRα pathways.(16) Furthermore, the PGC‐1α‐ERRα pathway induced CYP24A1 in the kidney in response to fasting. This evidence concerns the gene CYP2R1 and obesity due to melanocortin 4 receptor deficiency.