A small study, the results of which were published in the March issue of Pediatrics, showed that teens who switched from high-calorie drinks to noncaloric beverages lost a pound a month over a 6-month period. Researchers at Children's Hospital Boston had 103 teenagers switch to a noncaloric beverage for a half year and participate in discussions with researchers about their drink choices. Teens in the control group did not change what they were drinking, which included high-calorie drinks. The heaviest group of teens in the noncaloric drink group lost the equivalent of one pound a month. The results were significant enough to warrant a larger study, which will be sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases and the Charles H. Hood Foundation. Lead author Cara Ebbeling, the hospital's codirector of obesity research, pointed to the simplicity of the small study: "Most interventions ? take a very comprehensive approach, but?we targeted one behavior."

Ms. Farley is a freelance medical writer based in Wakefield, RI.