Energetic adaptations to weight loss in children and adolescents with obesity: a systematic review and meta-analysis.

Abstract

While weight loss often triggers adaptations to prevent further weight loss, these remain understudied and under-considered in the context of pediatric obesity. This systematic review and meta-analysis is the first to provide a comprehensive synthesis of the available evidence regarding the adaptations of the components of total energy expenditure (EE) in response to weight loss in children and adolescents with overweight/obesity (OW/OB), considering the intervention types (e.g., dietary, multidisciplinary, pharmacotherapy, bariatric surgery, or physical activity-based). Articles reporting on weight loss interventions of any type that included an assessment of EE based on indirect calorimetry were identified through a search of MEDLINE, EMBASE, and COCHRANE databases up to September 2024. Of the initial 1723 references found, 31 were included, representing 53 intervention arms. The meta-analysis revealed a small but non-significant decrease in resting EE (REE) after weight loss (Mean Change (MC) = -130.91 [-492.67, 230.86] kJ, p = 0.467), regardless of the intervention type. However, the systematic review suggests that the degree of weight loss and multidisciplinary studies (particularly those involving caloric restriction) appear to result in a greater decrease in REE, especially in girls, and during short-term interventions. REE relative to fat-free mass (FFM) (MC = -0.95 [-6.11, 4.21] kJ.kg^-1, p = 0.700) and physical activity-induced EE (PAEE) (MC = 45.47 [-22.93, 113.87] kJ, p = 0.155) were not meaningfully altered. The heterogeneity of the proposed intervention duration and the high inter-individual variability in body weight and composition changes could have contributed to these modifications. The present results highlight the need for further well-controlled and designed studies, especially when it comes to the thermic effect of food, and the need to consider the patients' individual profiles and responses to interventions.