Physiological and behavioural outcomes of a randomised controlled trial of a cognitive behavioural lifestyle intervention for overweight and obese adolescents

Abstract

This study evaluates the efficacy of the Choose Health program, a family-based cognitive behavioural lifestyle program targeting improved eating and activity habits, in improving body composition, cardiovascular fitness, eating and activity behaviours in overweight and obese adolescents. The sample comprised 29 male and 34 female overweight (n = 15) or obese (n = 48) adolescents aged 11.5-18.9 years (M = 14.3, SD = 1.9). Participants were randomly allocated to treatment or waitlist control conditions; waitlist condition participants were offered treatment after 6 months. DEXA-derived and anthropometric measures of body composition; laboratory-based cycle ergometer and field-assessed cardiovascular fitness data; objective and self-report physical activity measures; and self-report measures of eating habits and 7-day weighed food diaries were used to assess treatment outcome. Adherence to treatment protocols was high. Treatment resulted in significant (p < .05) and sustained improvements in a range of body composition (body fat, percent body fat, lean mass) and anthropometric measures (weight, BMI, BMI-for-age z-score and percentiles). Minimal improvements were seen in cardiovascular fitness. Similar results were obtained in completer and intention-to-treat analysis. Poor adherence to assessment protocols limits conclusions that can be drawn from physical activity and dietary data. Participation in the Choose Health program resulted in significant improvement in body composition. Longer-term follow up is required to determine the durability of intervention effects. Alternative approaches to the measurement of diet and physical activity may be required for adolescents.