Weight regain after bariatric surgery: A systematic review and meta-analysis of observational studies

Due to its significant impact on public health, obesity has been studied from a variety of perspectives. All surgical procedures of bariatric and metabolic surgeries (BMS) carry their risks and benefits and have specific characteristics. Considering that weight regain (WR) is considered a surgical failure. This systematic review, registered on PROSPERO under code CRD42023421203, aims to identify physical and behavioral predictors associated with WR post-BMS. Primary outcomes included WR prevalence after BMS (>10% recovery from maximum weight loss or points of BMI >4 or 5 kg/m²), while secondary outcomes assessed factors associated with WR. This systematic review with meta-analysis demonstrated that 49% of patients WR after BMS and this prevalence is higher in those who underwent Roux-en-Y Gastric Bypass (RYGB) surgery (42%) and in Europe (64%). Protective factors for WR only included prior BMI and younger age with statistical significance, however other analyzes did not demonstrate statistical significance. Therefore, it is important to note that the use of BMS does not guarantee long-term sustainable weight loss without continuous lifestyle modifications and treatment dietetic. Efforts to maintain weight loss should include ongoing lifestyle modifications to ensure the effectiveness and efficacy of the surgery.