ABSTRACT
Before initiating medical therapy, obesity must be understood as a lifelong, chronic, and relapsing disease that rarely responds completely to lifestyle modifications. Obesity is the accumulation of excess adipose tissue associated with an increased risk for diabetes mellitus, hypertension, dyslipidemia, stroke, gallbladder disease, sleep apnea, osteoarthritis, and certain cancers. The prevalence of obesity is rising in the U.S., with an estimated 64% of Americans classified as overweight or obese in 2000 [1]. Potential contributing factors to the increase in obesity include easy access to highly palatable and energy-dense foods, a relatively sedentary lifestyle, and a genetic legacy to preferentially store energy. Much of our evolutionary history involved surviving starvation such that, once adipose tissue accumulates, homeostatic neuroendocrine mechanisms resist attempts to diminish the supply of excess energy. When hypocaloric diets alone are used to reduce weight, a counter-regulatory increase in appetite and decrease in resting energy expenditure occur in an attempt to return the body to its former weight [2]. These metabolic changes make longterm maintenance of weight loss difficult to achieve. Pharmacologic therapy is frequently needed as an adjunct to lifestyle modifications for successful weight loss and maintenance.
