Weight loss in superobese patients has been problematic after conventional gastric restrictive operations including conventional Roux-en-Y gastric bypass (RYGB). The goal of the present study was to compare weight loss in patients with superobesity (body mass index > or =50 kg/m(2)) using a distal RYGB (D-RY) in which the Roux-en-Y anastomosis was performed 75 cm proximal to the ileocecal junction (N = 47) vs. patients who had Roux limbs of 150 cm (N = 152) and 50 to 75 cm (N = 99). All operations incorporated the same gastric restrictive parameters. Minimum follow-up was 3 years and ranged to 16 years. Weight loss and reduction in body mass index were significantly greater after D-RY vs. both RYGB-150 cm and short RYGB and in RYGB-150 cm vs. short RYGB through 5 years. Mean percentage of excess weight loss peaked at 64% after DRY, at 61% after RYGB-150 cm, and at 56% after short RYGB. Weight loss maintenance through 5 years was correlated with Roux limb length with D-RY greater than RYGB-150 cm greater than short RYGB. More than 95% of obesity-related comorbid conditions improved or resolved with weight loss. There was no difference in the early postoperative morbidity rates: 9% after D-RY; 8% after RYGB-150 cm; and 2% after short RYGB with one death (0.3%). All D-RY patients had at least one postoperative metabolic abnormality. Anemia was significantly more common after D-RY vs. the shorter RYGB with no difference in the incidence of metabolic sequelae between RYGB-150 cm and short RYGB. No operations were reversed or modified for nutritional complications. Two D-RY patients required total parenteral nutrition for protein malnutrition. These results show that Roux limb length is correlated with weight loss in superobese patients. However, the greater incidence of metabolic sequelae after D-RY vs. RYGB-150 cm calls into question its routine use in superobese patients undergoing bariatric surgery. We conclude that some degree of malabsorption should be incorporated into bariatric operations performed in superobese patients to achieve satisfactory long-term weight loss.