Preoperative very low-calorie diet and operative outcome after laparoscopic gastric bypass: a randomized multicenter study.

HYPOTHESIS A 14-day very low-calorie diet (VLCD) regimen before a laparoscopic gastric bypass procedure will improve perioperative and postoperative outcomes. DESIGN Multicenter, randomized, single-blind study. SETTING Five high-volume bariatric centers in Sweden, the Netherlands, Lithuania, Spain, and Belgium. PATIENTS Two hundred ninety-eight morbidly obese patients undergoing laparoscopic gastric bypass from March 1, 2009, through December 5, 2010. INTERVENTION Patients were randomly allocated to a 2-week preoperative VLCD regimen or no preoperative dietary restriction (control group). MAIN OUTCOME MEASURES Operating time, surgeon's perceived difficulty of the operation, liver lacerations, intraoperative bleeding and complications, 30-day weight loss, and morbidity. RESULTS Mean (SD) preoperative weight change was -4.9 (3.6) kg in the VLCD group vs -0.4 (3.2) kg in the control group (P < .001). Although the surgeon's perceived difficulty of the procedure was lower in the VLCD group (median [interquartile range], 26 [15-42] vs 35 [18-50] mm on a visual analog scale; P = .04), no differences were found regarding mean (SD) operating time (81 [21] vs 80 [23] min; P = .53), estimated blood loss (P = .62), or intraoperative complications (P = .88). At the 30-day follow-up, the number of complications was greater in the control compared with the VLCD group (18 vs 8; P = .04). CONCLUSIONS Although weight reduction with a 14-day VLCD regimen before laparoscopic gastric bypass performed in high-volume centers seems to reduce the perceived difficulty of the procedure, only minor effects on operating time, intraoperative complications, and short-term weight loss could be expected. However, the finding of reduced postoperative complication rates suggests that such a regimen should be recommended before bariatric surgery.