Background: The aim of this study is to describe the effects of a prolonged dietary-behavioral-physical activity
intervention (24 months) on body composition in a group of adolescents with obesity.
Methods: Longitudinal study in 196 individuals with obesity (86 boys and 110 girls) aged 10.1–14.9 years that
completed a prolonged combined intervention (24 months). Values for weight, height, skinfold thickness, waist
circumference, BMI, body fat, fat mass index (FMI) and fat-free mass index (FFMI) were registered or calculated. A
good response to treatment was reported when a BMI z-score reduction of greater than or equal to 0.5 units of the
initial value occurred after 24 month of follow up.
Results: A good response after 24 months of follow-up reached 58.2% (n = 114). In boys with obesity and BMI status
improvement, weight z-score, BMI z-score, body fat, and FMI significantly decreased (p < 0.05). In girls with obesity and
BMI status improvement, weight z-score, BMI z-score, waist circumference, waist z-score, body fat and FMI significantly
decreased (p < 0.05). In both sexes the height and FFMI increased significantly (p < 0.05). The multiple logistic
regression analysis showed that girls and younger age were associated with BMI status improvement; concurrently, the
place of residence (urban or rural) and degree of obesity were not associated with BMI status improvement.
Conclusion: The application of long-term combined strategies in the treatment of childhood obesity seems to be
effective. As BMI decreases, a reduction in fat mass is also detected, with evident sexual dimorphism, in the absence of
changes in fat-free mass and, consequently, in longitudinal growing