By using whole body GDF15 or FGF21 knock out mouse models in conjunction with Crif-1 deletion in liver, the authors concluded that GDF15 is necessary to regulate body mass and fat mass and to prevent diet-induced hepatic steatosis, whereas FGF21 is requited to improve insulin sensitivity, energy expenditure and thermogenesis in WAT (32). Here, FGF21 is linked to Hepatic steatosis.