The prevalence of overweight and obesity is increasing worldwide. During the last two decades, the prevalence of adults in the higher body mass index (BMI) categories in the US has increased the most, as much as 300% for those with a BMI above 40kg/m2. In children and adolescents, a doubling of the prevalence of severe overweight poses a serious health risk to future generations of young adults who may develop chronic diseases normally associated with aging. The simple definition of obesity, an imbalance between energy intake and energy expenditure, ignores the complexity of, and largely unknown interactions between, genes, food intake and physical activity, which together determine bodyweight and fat distribution. Although the etiology and manifestations of overweight and obesity are complex, the assessment of overweight and obesity requires only an accurate measurement of bodyweight, height and abdominal circumference, as well as a history and physical examination attuned to the morbidities that commonly accompany overweight and obesity such as diabetes mellitus, hypertension, dyslipidemia and sleep apnea. The treatment of patients with overweight and obesity continues to be based on changes to diet and physical activity. Simple behavior modification techniques are within the reach of busy clinicians. The additional use of available bodyweight reduction medications can reliably lead to a 5 to 10% reduction from initial bodyweight, a loss that has been shown to provide significant health benefit. The use of meal replacements has also been shown to be effective and is probably an under-appreciated treatment resource. Surgery is the most successful treatment for those with severe obesity and should be discussed as an option for those in the appropriate bodyweight categories. Because societal trends favor the greater intake of calorie-dense foods and less physical activity to accomplish the activities of daily life, the future of obesity treatment will require the development of bodyweight reduction medications that work by a variety of mechanisms to decrease food intake or increase energy expenditure. Such medications should not be viewed as a 'crutch' but rather as a 'helping hand' that enable people to better adhere to a healthier lifestyle.