"Our hope is that schools after seeing these outcomes will say, 'Hey, we want to implement this in our curriculum,'" Bernadette Melnyk, from The Ohio State University in Columbus, told Reuters Health.
Melnyk developed the COPE (Creating Opportunities for Personal Empowerment) Healthy Lifestyles TEEN (Thinking, Emotions, Exercise, Nutrition) program, and is the lead author of the new study.
One-third of young people in the U.S. are overweight or obese, she and her team note. Obese teens are at higher risk of depression and are more likely to perform poorly in school.
However, most programs targeting youth obesity don't also address mental health, Melnyk said.
"Unless we change the way that people are thinking, there's less likelihood that any behavioral change is going to sustain," she added.
The COPE program is designed to help teenagers recognize and change irrational and negative thoughts.
"We teach the teens that how they think directly relates to how they feel and how they behave," Melnyk said.
Other components include education on healthy lifestyles, self-esteem building, goal-setting and problem-solving, coping with stress and regulating emotion and behavior. Each of the 15 weekly sessions also includes 20 minutes of walking, dancing or other exercise.
To investigate the effects of the program, the researchers enrolled 14- to 16-year-olds taking health education classes at 11 high schools in the southwestern U.S.
Students at one set of randomly-selected schools participated in the COPE program and others were assigned to a program called Healthy Teens, which focused on topics like road safety and skin care.
In total, 374 teenagers were chosen to take part in COPE and 433 in Healthy Teens.
Immediately after the 15-week program, teens who participated in COPE were taking more steps per day - 13,681 versus 9,619 - based on pedometer readings.
They also had a lower average body mass index, a measure of weight in relation to height, than their peers who participated in Healthy Teens. The effect was small, however - equivalent to about a one-pound difference in weight.
Thirteen percent of the students in COPE reported having had at least one alcoholic drink in the past month, versus 20 percent of those enrolled in Healthy Teens.
Six months later, the proportion of teens that were overweight had fallen in the COPE group - from 44 percent before the program to 41 percent after. The opposite trend was seen among the Healthy Teens group, the researchers wrote in the American Journal of Preventive Medicine.
According to the students, the most helpful aspects of the program were the sections on stress and coping and nutrition and exercise.
Deborah Gonzalez was working as the assistant superintendent at one of the school districts included in the study. She has since joined ASU Preparatory Academies in Tempe, Arizona, as chief academic officer, and has helped the school expand COPE into a year-long program.
"We've been using it now for the past three years as a required course for all freshmen," Gonzalez told Reuters Health.
"The anecdotal feedback that we get from the students is that they are much more aware and conscious of being healthy and making healthy choices."
Gonzalez said teachers have also observed that students have more positive attitudes after taking part in the course.
"It's less about not being negative in their thinking and more about being empowered," she added.
"They truly feel like they can come up with solutions to problems, and they can be the people who positively and proactively decide what's going to happen ... they see themselves as students who are smart and capable and students who can help one another."
SOURCE: http://bit.ly/18rneSj American Journal of Preventive Medicine, online September 10, 2013.