Under nutritional deficiency, fibroblast growth factor-21 (FGF21) signaling activates the global expression of autophagy-related genes through the histone H3K27-ME3 demethylase Jumonji-D3 (JMJD3/KDM6B), thus mediating lipid degradation [11]. This evidence concerns the gene FGF21 and nutritional deficiency disease.