Can a school based programme in a natural environment reduce BMI in overweight adolescents?

Current levels of obesity amongst adolescents may be largely attributed to changes in environmental exposures that place vulnerable youth at risk, yet few studies have incorporated environmental approaches to normalising Body Mass Index (BMI). Our hypothesis is that a live-in school based programme in a natural environment can reduce the BMI of overweight children. The pilot study therefore explores the effects of such a programme on the BMI of adolescents in rural Victoria, Australia. Year 9 students (15 year olds, N = 1021) at a rural school with a physically demanding, 10-month, live-in outdoor programme had their BMIs measured at the beginning and end of the programme. Their observed BMI at the end of the programme was compared to expected BMI (based on adjustment of their initial BMI to account for normal growth using international standards). Participation in the programme reduced the BMI of boys who were in the normal to obese range (χ(2) = 8.57, p = 0.014), but not in girls. For the overweight and obese boys BMI decreased by up to 2.5 kg/m(2). These results suggests that school based environmental interventions may be effective in reducing obesity in adolescents, supporting our hypothesis. Our study is limited by its opportunistic observational nature, but it nevertheless suggests that such a live-in school programme in a natural environment may provide a valuable addition to the list of interventions available to combat the obesity epidemic. Although the programme reduced BMI in boys, the equivocal data for girls means that even an intensive programme such as this struggles to achieve a significant change in BMI across all obese adolescents. Our study nevertheless supports the need for further investigation of the possible contribution of school based programmes in natural environments to interventions to fight the obesity epidemic--because there is no magic bullet.