Differential effects of dietary and physical activity interventions on adiposity of children with obesity.

Abstract

Background: Managing obesity in children remains challenging. In addition to body mass index (BMI), incorporating body composition into evaluations of postobesity interventions would help assess changes in adiposity.

Purpose: This study aimed to identify the relationship between dietary intake, physical activity, and changes in BMI z scores and adiposity among children with obesity.

Methods: Children aged 7-15 years with obesity received monthly dietary and physical activity instructions for 6 months. Three-day dietary records and physical activity questionnaires were collected at 0, 3, and 6 months. Body composition was measured using bioelectrical impedance analysis. These relationships were analyzed using uni- and multivariate linear regression analyses.

Results: A total of 155 children with obesity completed the 6-month study. A higher total protein intake per ideal weight for height was significantly correlated with a decrease in BMI z score and trunk fat mass index (trunk fat mass [FM] in kg/height in m2). Mean dietary fiber intake was negatively correlated with BMI z score, FM, FM index (FMI, FM in kg/height in m2), and visceral fat area (VFA) at 6 months. Each 1 g/kg/day increase in protein intake and additional 1 g/day of dietary fiber intake led to a 0.191 kg/m2 (95% confidence interval [CI], -0.309 to -0.072) and 0.028 kg/m2 (-0.05 to -0.005) reduction in BMI z score. Each 1 g/day increase in protein intake led to a reduction of 0.009 kg/m² in trunk FMI (-0.016 to -0.002) and 0.21 cm² in VFA (-0.418 to -0.002). The outcomes observed at 6 months were consistent with the overall 6-month findings, reinforcing the efficacy of the intervention.

Conclusion: Our study showed beneficial effects of high dietary protein and fiber intakes on BMI z scores and adiposity of children with obesity. Fine-tuning dietary interventions that emphasize appropriate protein and fiber intakes may be more practical for managing childhood obesity.