Implementation of Preoperative Very Low-Calorie Diets in Preparation for Metabolic and Bariatric Surgery

Very low-calorie diets (VLCDs) have been commonly implemented prior to metabolic and bariatric surgery (MBS) with the goal of shrinking left liver lobe size and reducing intra-abdominal mesenteric fat. Through this manuscript, we aimed to review the available literature discussing the types of VLCDs, their mode of implementation, preoperative duration, and the intraoperative and postoperative measures. A total of 103 articles was used in the generation of this review, including 3402 MBS candidates across the studies. VLCD was shown to induce significant preoperative weight loss, reduction in body fat mass, glycemic improvement, and decrease in proinflammatory makers. Liver volume reduction of 5%-23% and abdominal wall circumference reduction of 2.0-8.5 cm were noted following short regimens of VLCD, leading to improvement in perceived intraoperative difficulty. Postoperatively, metabolic improvements and reduction in perioperative complication rates were observed in some studies. In conclusion, VLCD demonstrated potential preoperative, intraoperative, and postoperative improvements in patients undergoing MBS.