In the new study, weight differences in girls who did and didn't go through the program were small, but persisted for at least a few months after the sessions ended.

"It didn't have a massive impact," said Alison Field, who studies weight gain and weight control at Children's Hospital Boston and wasn't involved in the new study.

Still, she told Reuters Health, the program "addressed a variety of issues, some related to obesity and also just helping them deal with body image, which I thought was very important and often overlooked."

Most programs that have tried to get overweight teens to keep off the pounds haven't had long-term success, according to the Oregon-based researchers.

The study included 208 overweight and obese girls age 12 to 17. At the outset, the researchers randomly split the girls into two groups: one that got normal care from their pediatricians, and the other that went to 16 healthy lifestyle and weight management group meetings, held over five months.

At those sessions, girls reviewed their own food and physical activity records and discussed issues that commonly affect heavy girls, including depression and emotional eating. Those adolescents were also advised to cut their calories to 1,600 to 1,800 per day and to eat regular meals, exercise at least five days a week, practice yoga regularly and limit television time.

Parents of youth in the intervention group were invited to separate meetings, and the girls' pediatricians got extra coaching on how to help them reach their health and lifestyle goals.

Those girls started the study at an average weight of 190 pounds. After five months of meetings, they held steady at that weight. Another seven months after the program ended -- a year from the start of the study -- their weight crept up to 195 pounds, on average.

The weight gain may have been due to the fact that some of the girls were still growing.

In comparison, the adolescents that got their usual care started out at an average of 186 pounds and climbed to 190 at five months and 194 at one year -- putting on more extra weight during the study than girls that had the weight-management intervention.

Body mass index, a measure of weight in relation to height, dropped a bit closer to the normal range in the intervention group than in the comparison group over time.

The researchers reported in the journal Pediatrics on Monday that girls who went through the diet and lifestyle program also ended up eating less fast food and feeling better about their bodies than those who didn't.

However, there was no difference over time between the two groups in cholesterol or blood sugar readings, which may predict future heart disease and diabetes.

"This intervention that we tested was modestly effective," said Victor Stevens, from the Kaiser Permanente Center for Health Research in Portland, who worked on the study.

"I don't think it's ready to be disseminated yet. I think we're going in the right direction."

Stevens said working with girls' parents and pediatricians, as well as the teens themselves, were promising elements to work into future programs. So was seeing the girls in groups -- they seemed to bond and get support from shared experiences, he said.

IS IT SUSTAINABLE?

It's hard to know at this point how much a similar program would cost outside of a research environment.

"It was very labor-intensive, so I don't know how sustainable that would be, or how you could ramp that up on a bigger scale," Field said.

Stevens said that it's especially important to address obesity in teens, before they become obese adults with all of the health risks that come with carrying extra weight. But finding the most effective way to do it hasn't been easy.

"The environment in which we live now pushes us constantly toward obesity. There's easy availability of cheap, attractive, high-calorie food. Add to that an environment in which we really don't have to exercise very much," Stevens said.

"Whatever programs we come up with in the healthcare world to push back against those forces are going to have to be fairly strong."

SOURCE: bit.ly/wufQSr Pediatrics, online February 13, 2012.

$INS01; Line LNY Insave:- TI line name (Map report)

• A Permanent Economic Emergency