Autophagy degrades cytoplasmic contents to achieve cellular homeostasis. We show that selective loss of autophagy in hypothalamic proopiomelanocortin (POMC) neurons decreases α-melanocyte-stimulating hormone (MSH) levels, promoting adiposity, impairing lipolysis and altering glucose homeostasis. Ageing reduces hypothalamic autophagy and α-MSH levels, and aged-mice phenocopy, the adiposity and lipolytic defect observed in POMC neuron autophagy-null mice. Intraperitoneal isoproterenol restores lipolysis in both models, demonstrating normal adipocyte catecholamine responsiveness. We propose that an unconventional, autophagosome-mediated form of secretion in POMC neurons controls energy balance by regulating α-MSH production. Modulating hypothalamic autophagy might have implications for preventing obesity and metabolic syndrome of ageing.