Sleeve gastrectomy (SG) was originally performed as the restrictive component of the duodenal switch procedure. This partial vertical gastrectomy served to reduce gastric capacity and initiate short-term weight loss while the malabsorptive component of the operation (biliopancreatic diversion) provided the long-term weight loss. Some patients, however, could not undergo the intestinal bypass, and early investigations found that substantial weight loss occurred with the SG alone. The sleeve then developed into a risk management strategy for very large or high-risk patients who would not tolerate a longer or higher-risk procedure.