The present invention provides methods of treating or preventing disorders or conditions associated with an undesirable level of a satiety factor by administering to a subject in need thereof an effective amount of an agonist or antagonist of a satiety factor. The present invention also provides methods of selecting a subject for therapy with an agonist or antagonist of a satiety factor. Exemplary disorders or conditions associated with an undesirable level of a satiety factor include overweight, obesity, metabolic disorders, hypertension, lipid related disorders, anorexia and type II diabetes.