The beneficial effects of the intervention on the excess BMI increase ( +0.01 vs +0.34 kgm ( -2 ) in the intervention and control groups , respectively ) and on the overweight incidence in initially non-overweight students ( 4.3 % vs 8.6 % ; odds ratio = 0.48 ( 95 % confidence interval : 0.23-1 .01 ) ) were maintained at the post-trial follow-up .