Early Postoperative Weight Loss Trajectories Predict Weight Regain at 18 Months Following Bariatric Surgery

Background: Early postoperative total weight loss percentage (TWL%) shows heterogeneous predictive value for subsequent outcomes, yet targeted management strategies remain challenging. Identifying distinct early weight loss trajectories could characterize high-risk populations for weight regain, enabling proactive interventions to optimize long-term outcomes. Methods: This prospective observational study was conducted from April 2023 to December 2024. Dynamic weight data were recorded at 1, 3, 6, and 18 months postoperatively; TWL% was calculated. Latent Growth Curve Modeling (LGCM) was used to construct early weight loss trajectory models. Logistic regression analyzed associations between early weight loss trajectories and weight regain risk. Results: A total of 215 patients were included in the study. Weight regain incidence was 23.26%. LGCM identified two TWL% trajectory groups: rapid weight loss group and slow weight loss group . Taking the slow weight loss group as reference, rapid weight loss group had significant lower risk in the incidences of weight regain [Odds ratio (OR) = 0.441, p = 0.044]. Conclusion: Two distinct early postoperative weight loss trajectories were identified, with the rapid weight loss group demonstrating significantly lower weight regain at 18 months. Early weight loss patterns are correlated with medium-term outcomes through more effective resetting of body weight set points.