Since classic autophagy is known to be activated principally by pathways that mediate the nutrient deficiency/low energy state that induces AMPK and inhibits mechanistic target of rapamycin (mTOR) activity [20], it would be expected that obesity—a chronic state of nutrient overabundance—is associated with the downregulation of autophagy. Here, MTOR is linked to obesity due to melanocortin 4 receptor deficiency.