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

Introduction: 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).

Methods: 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).

Results: 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.

Conclusion: 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.