Supplementary Material for: Predictors of Body Weight Loss and Body Weight Loss Maintenance in Children and Adolescents Following Inpatient Multidisciplinary Obesity Treatment

Introduction: To improve pediatric obesity treatment, this study aimed to identify predictors of body weight loss (BWL) and its maintenance (BWLM) in children and adolescents. Methods: Data from 59 hospitalized children and adolescents with obesity (aged 9-17, mean 13.4 ± 1.9 years; mean length of stay: 38 ± 9.1 days) were collected at admission (T1), at discharge (T2) and up to 24 months thereafter (T5). Predictors of BWL (ΔT1-T2) (mean 0.33 ± 0.14 BMI z-score) and BWLM (ΔT2-T5) were categorized into demographic, psychometric, and sociometric data, physical condition, autonomic nervous system functions, and eating behavior. Secondary outcomes included changes in body composition and motor performance. Predictors were analyzed using LASSO and hierarchical regression. Results: Energy density and food intake consistently predicted BWL and BWLM. Body dissatisfaction (p=.016), better anger management (p=.031), smell identification skills, higher initial motor performance and strength, and lower initial endurance predicted BWL. A positive attitude towards healthy eating (p<.001), its improvement (p=.027), reduced parasympathetic withdrawal (p<.022), and high salt sensitivity (p<.001) predicted BWLM. Conclusion: This study advances understanding of BWL and BWLM in pediatric obesity, emphasizing the key role of energy intake and its interplay with psychological and physiological factors.