Determinants of Weight Loss and Regain in Men After Roux-En-Y Gastric Bypass: A Retrospective Analysis

Men constitute a minority of bariatric surgery patients despite facing a high burden of obesity-related complications. Little is known about factors influencing long-term weight outcomes in male patients. We aimed to identify clinical and behavioral determinants of weight loss maintenance and weight regain in men after Roux-en-Y gastric bypass (RYGB). We retrospectively reviewed 100 men with obesity who underwent laparoscopic RYGB between 2013 and 2016. Inclusion was limited to those with ≥2 years of postoperative follow-up, yielding 43 patients for analysis. Clinical variables (age and comorbidities), behavioral factors (exercise and dumping syndrome - DS), and weight data were collected. Poisson regression identified factors associated with achieving normal body mass index (BMI) and significant weight regain. A linear regression model assessed predictors of percent excess weight loss (%EWL). Paradoxically, men who achieved a normal BMI postoperatively had a higher risk of significant weight regain. Specifically, achieving a normal BMI was associated with a greater likelihood of ≥20% of total weight lost regained (adjusted prevalence ratio [PR] ~2.5, p<0.05). Longer follow-up duration was also associated with increased weight regain. On the other hand, the presence of DS was strongly associated with successful weight loss: men reporting dumping had a higher probability of attaining normal BMI (adjusted PR ~2.9, p<0.05). No other factors (age, baseline comorbidities, or exercise) showed significant associations with weight outcomes. RYGB is effective in men, leading to substantial weight loss and improvement in comorbidities. However, early success (achieving a normal BMI) did not guarantee long-term weight stability, as those patients were more prone to weight regain. These findings highlight the need for extended follow-up and targeted support in male bariatric patients to sustain weight loss outcomes.