Mechanism for the effects of FGF21Fibroblast growth factor 21 (FGF21) has a wellestablished role in modulating macronutrient uptake,it is produced by the liver in response to high-carbohydrate ingestion to signal to the brain to reduce carbohydrate intake and also has a role in modulating the preference for sweet-tasting foods and drinks. However,the neural pathways underlying these effects have been unclear. New work published in Cell Metabolism offers a potential mechanism for the effects of FGF21