Food intake declines throughout the life span. This physiologic anorexia of aging is caused in part by alterations of stomach-fundus compliance and release and activity of cholecystokinin. In addition, the decline in testosterone in males results in elevated leptin levels that increase the anorexia. There is also evidence that cytokines play a role in the pathogenesis of anorexia and sarcopenia, thus accelerating the development of frailty in older persons. Numerous treatable causes of anorexia and weight loss exist. Depression is the most commonly diagnosed cause of pathologic weight loss in older persons.