Remarkably, deletion of Bmal1 in astrocytes in mice is sufficient to phenocopy the obesity, INS resistance, and glucose intolerance of Bmal1-/- constitutive KO mice (39), suggesting that robust astrocyte circadian rhythms could preserve whole-body homeostasis and metabolic health. Here, BMAL1 is linked to obesity due to melanocortin 4 receptor deficiency.