The present invention relates t o BMPs (bone morphogenetic proteins) which regulate metabolic homeostasis of iron, fats and carbohydrates. In particular, the present invention relates t o methods for treating a disease of iron metabolism or a disease comprising abnormally high or low hepcidin levels or abnormally high or abnormally low iron levels using a BMP agonist or antagonist. The present invention further relates t o methods for treating a disease of fat or carbohydrate metabolism using a BM Pagonist or antagonist. The present invention further relates t o methods for treating a disease of iron metabolism or treating a disease of fat or carbohydrate metabolism by inhibition of the interaction between BMPs and erythroferrone (ERFE) / FAM 132b.