Association of a 'three meals and sleep routine' lifestyle intervention with weight and metabolic health in children with obesity: a prospective, single-arm pilot study.

Abstract

Background: Intensive health behavior and lifestyle treatment is the foundation of pediatric obesity care, but sustained adherence and weight-loss maintenance remain difficult. Regular meal and sleep timing may complement standard care, although pediatric interventional evidence is limited. This prospective, single-arm pilot study aimed to evaluate longitudinal changes in weight, body composition, and metabolic markers during a 'three meals and sleep routine' (TMSR) intervention.

Methods: This prospective, single-center, single-arm pilot study consecutively included 119 children with obesity aged 5-18 years [body mass index (BMI)-for-age Z-score (BAZ) >2] from January 2022 to December 2023. Families received nutritionist-led written guidance for three structured meals per day, no caloric intake between meals, age-based energy targets of 1,500-2,300 kcal/day, a protocol-defined minimum of 7.5 hours of nighttime sleep with lights off by 22:30, and maintenance of habitual physical activity. Follow-up was planned at approximately 2-month intervals but occurred according to clinical availability. Anthropometry, bioelectrical-impedance body composition, and fasting metabolic markers were assessed. Adherence, dietary intake, sleep, and physical activity were not objectively monitored. Generalized linear mixed models used available repeated measurements to estimate average within-cohort change over time.

Results: The cohort had a mean age of 10.24±2.33 years; 82 participants (68.9%) were male and 37 (31.1%) were female. The fitted BMI trajectory decreased from approximately 26.0 kg/m² at baseline to 24.5 kg/m² at month 4, then increased to 25.4 kg/m² by month 12. BAZ followed the same pattern, decreasing from 2.9 to 2.3 before increasing to 2.4. Visceral fat area and percentage body fat also declined through month 4 and subsequently rebounded. Fasting insulin and glucose showed early declines followed by partial rebound, whereas triglycerides and serum uric acid declined across follow-up. In linear-time models, average monthly coefficients were negative for BMI, BAZ, visceral fat area, percentage body fat, fasting insulin, glucose, triglycerides, and serum uric acid. These coefficients summarize within-cohort associations and do not capture the observed nonlinear trajectories.

Conclusions: In this uncontrolled cohort, several anthropometric and metabolic measures improved during the first 4-6 months, but BMI, BAZ, adiposity measures, insulin, and glucose later showed partial rebound. The findings are preliminary and hypothesis-generating; the absence of a comparator and objective adherence data precludes causal attribution to TMSR and limits assessment of durability and safety. Controlled, multicenter studies with age-appropriate sleep targets and objective behavioral monitoring are needed.