By Anne Harding

An Internet programme that requires just a half-hour on line each week can reduce binge eating among at-risk teens, while helping them to maintain a healthy weight, California researchers report.

What's more, the 16-week programme was effective even though most participants used it for less than eight weeks.

Concerns have been raised that efforts to fight obesity among young people could actually contribute to eating disorders, but the findings show that it's possible to fight obesity and unhealthy eating behaviours simultaneously, Megan Jones, one of the study's authors and a doctoral candidate at Stanford Medical Centre in California, told Reuters Health.

"Creative solutions are really needed to address the obesity epidemic in this country," Jones said in an interview. "This study suggests that the Internet can be an effective vehicle for providing these interventions."

As many as one quarter of overweight girls and nearly 13 percent of overweight adolescent boys may engage in binge eating, she added. While these episodes may not meet the medical definition of binge eating, Jones pointed out, "it doesn't need to reach clinical criteria to have a lot of the same medical and psychological consequences." These can include negative mood and, clearly, weight gain, given that a person may consume 1 500 calories during a binge.

Jones and her team developed a 16-week online intervention modelled on an eating disorder prevention programme. Known as SB2-BED, it uses psychoeducation and behavioural intervention such as stimulus control and self monitoring, all aimed at reducing binge eating and sedentary activities, increasing healthy eating and physical activity, and maintaining weight.

The researchers randomly assigned 105 male and female high school students, who were at risk for becoming overweight, to participate in the program or to join a wait-list "control" group.

Compared to the control group, the students in the intervention group had significantly lower body mass indexes after completing the programme. They also reported significantly fewer episodes of binge eating and reduced weight and shape concerns, according to the report in the medical journal Pediatrics.

Individuals who had reported engaging in binge eating at the study's outset showed an even greater reduction in BMI.

Jones and her team are now working on a second version of the programme, which is likely to include a text messaging component to improve adherence, as well as involvement of parents and peers and in-person coaching to encourage physical activity.

While the programme will likely be shorter than 16 weeks, Jones said, she and her colleagues are planning to include quarterly booster sessions to help participants maintain a healthy weight. "With weight management it's really the maintenance, the long-term change, that's hard to achieve," she said.