Update on obesity treatment.

Although the formula for weight control is a simple matter, namely ensure that calories consumed equals calories expended, its implementation is a source of great frustration for an estimated 85 million Americans. This results in an estimated 40 billion dollars spent each year in health and related treatment costs. This review outlines the epidemiology, health consequences, and treatment of obesity with an emphasis on newer developments in our understanding of the etiology of obesity and its treatment.