Figure 1.

Fibroblast Growth Factor 21 (FGF21) induction by nutritional inputs. Low protein diet, carbohydrates intake, fat consumption, ketogenic diets and fasting are nutritional signals that induce the hepatic expression of FGF21 through different transcription factors. FGF21 as an endocrine factor exerts its metabolic effects mainly in the adipose tissues, directly or indirectly via a liver-hypothalamus axis. The metabolic effects of FGF21 look for restoring metabolic homeostasis by activating different metabolic pathways, but also by changing the macronutrient preferences and the feeding behavior.