Environmental factors in the etiology of obesity in adolescents.

As the prevalence of obesity increases in children and adults from the United States and around the world, the interest in prevention is also increasing. For obesity prevention to have a chance to be successful, it should be based on evidences of risk factors rather than on empiric interventions. Selected risk factors for obesity present during adolescence are reviewed, such as television viewing, consumption of sugar-containing beverages, familial and socioeconomic environment, and recent changes in US society. The International Obesity Task Force's conceptual framework of environmental factors in the development of obesity is presented, as well as practical implications for obesity prevention and treatment in adolescence.