Abstract
One-anastomosis gastric bypass is currently a common procedure in bariatric and metabolic surgery. This procedure, based on a single-loop gastroenteric anastomosis (biliopancreatic loop) with a long, narrow stomach, has a mixed mechanism of action (restriction and malabsorption). However, the biliopancreatic loop, and in particular its length, is considered responsible for the degree of malabsorption, but the most appropriate or "optimal" biliopancreatic loop length remains a subject of debate. This literature review examines the relationship between biliopancreatic loop length, selected using various methods, and postoperative weight loss and nutritional deficiencies.