Anorexia nervosa (AN) is the deadliest mental illness affecting females 9 times more than males. The estimated financial costs due to healthcare, productivity losses, informal care and efficiency cost totaled $11.2 Billion in 2018. We have developed a method to treat AN using a novel mechanism. We have discovered TET3 as a molecular, and the hypothalamic AGRP neurons as a cellular, target of our method. Our method is also effective in treating cancer cachexia, a wasting syndrome characterized by anorexia, weight loss, and elevated energy expenditure. 80% of cancer patients world-wide suffer from cachexia and 30% die directly form cachexia. Currently, no FDA-approved drugs are available for treating AN and cancer cachexia.