Time-Restricted Eating for Weight-Loss Maintenance

Weight regain after intentional short-term weight loss is a common challenge. It often undermines the long-term benefits of obesity treatment. This study is a multi-center 2-arm randomized controlled trial across six regions in China, specifically targeting overweight or obese adults who have recently achieved a short-term weight reduction (≥5% of body weight). The trial will evaluate whether a 10-hour daily Time-Restricted Eating (TRE) regimen can more effectively prevent weight regain compared to standard weight maintenance counseling alone. Both the intervention and control groups will receive the same frequency and intensity of nutritional counseling for weight maintenance; the only difference is that the TRE group will be instructed to confine their daily eating to a self-selected 10-hour window, while the control group has no eating window restriction. In addition to the primary outcome of weight regain, the study will explore potential mechanisms underlying the effects of TRE and assess secondary outcomes including changes in body composition, metabolic health, and quality of life. This study recruits participants from six distinct regions across Eastern, Western, Southern, Northern, and Central China to enhance national representativeness. The study is divided into two phases: the first phase is a 2-month weight loss run-in phase (the screening phase), during which participants will receive standardized lifestyle and diet guidance from trained dietitians. Those who achieve at least a 5% loss of initial body weight by the end of this phase-and maintain a stable weight for approximately three weeks-will proceed to the second phase. In the second phase, participants will be randomly assigned to one of two arms for a 12-month weight maintenance intervention. The Control Arm will receive periodic weight-management nutritional counseling without any eating time restriction, while the TRE Intervention Arm will receive the same guidance plus instructions to follow a daily 10-hour time-restricted eating schedule. This design ensures both groups receive equivalent dietary and lifestyle support, with TRE as the key differential strategy. Following the 12-month intervention phase, participants will be followed for an additional 12 months (without active intervention) to observe longer-term weight outcomes. Data will be collected at multiple time points: baseline (before the weight loss phase), 2 months (end of the weight loss phase and prior to the start of the maintenance phase), 5 months, 8 months, 14 months (end of the weight maintenance phase), as well as 20 months and 26 months (during the post-intervention follow-up). Key outcomes include changes in body weight (to assess weight regain or maintenance), body composition, metabolic health indicators (e.g. blood glucose, lipids), and quality of life measures. To monitor dietary behaviors, participants will be asked to upload meal photos via a designated mobile application with automatic time-stamping, which will be used to assess eating timing and adherence to the prescribed eating window. Body weight will be measured once weekly using Bluetooth-enabled smart scales. To explore potential mechanisms of action, biospecimens (blood and stool) will be collected at baseline, 2 months, 8 months, and 14 months for analysis. In addition, Continuous Glucose Monitoring (CGM) will be performed in a randomly selected subsample of 200 participants (100 from each group) using a standardized device for 14 consecutive days at months 2, 8, and 14. These data will be used to evaluate glycemic stability and adherence to the assigned eating window. Real-time CGM readings will not be disclosed to participants and will not be used to guide individual-level interventions.