BACKGROUND:Early lifestyle intervention with overweight and obese adolescents could help to avoid serious health events in early adulthood, ultimately alleviating some of the strain on the public health system due to obesity-related morbidity. Commercial weight loss programs have wide reach into the community setting, and have demonstrated success in long term weight management in adults, beyond that of current public health care. Commercial weight-management programs have not been evaluated as a method of delivery for overweight and obese adolescents. This study aims to evaluate the efficacy of a new adolescent weight management program in a commercial environment. METHODS:One hundred and forty adolescents, 13 to 17 years old, will be randomised to either a weight management program intervention or a wait-listed group for 12 weeks. The commercial program will consist of a combined dietary and lifestyle approach targeting improved health behaviours for weight-loss or weight-stability. Participants will be overweight or obese (above the 85(th) percentile for BMI) and without existing co-morbidities. Outcome measures will be assessed at baseline and after 12 weeks. Primary outcome measures will be changes in BMI Z-score and waist-height ratio. Secondary outcome measures will include changes in behaviour, physical activity and psychosocial wellbeing. Intervention participants will be followed up at 6 months following completion of the initial program. Ethics approval has been granted from the Monash University Human Research Ethics Committee (CF11/3687-2011001940). DISCUSSION:This independent evaluation of a weight management program for adolescents, delivered in a commercial setting, will provide initial evidence for the effectiveness of such programs; which may offer adolescents an avenue of weight-management with ongoing support prior to the development of obesity related co-morbidities. TRIAL REGISTRATION:The protocol for this study is registered with the International Clinical Trials Registry ISRCTN13602313.