FGF21 and Obesity: Whether the effect of FGF21 on obesity is mediated by eating behavior, or changes in FGF21 and the disinhibition domain are driven by obesity (BMI) itself, or whether FGF21 is a confounder of the association between disinhibition and BMI will need to be clarified in further studies focusing on mechanistic pathways underlying changes in FGF21 concentrations.