The term "obesity" refers to an excess of fat. As the prevalence of obesity increases, so does the prevalence of the comorbidities associated with obesity. The general consensus is that excess intake of calories from any source causes weight gain and obesity. The goal of therapy is to prevent, reverse, or ameliorate the complications of obesity. The choice of therapy is dependent on several factors including the degree of overweight or obesity and patient preference. The optimal management of overweight and obesity requires a combination of diet, exercise, behavioral modification, pharmacologic therapy, and bariatric surgery.