Pop LM, et al. - An inquiry was set up regarding the physiological mechanisms causing rapid improvement in diabetes after Roux-en-Y Gastric Bypass (RYGB), with emphasis on the roles of concurrent peri-operative dietary restrictions, which could alter glucose metabolism. The primary contributor to the rapid improvement in glucose metabolism following RYGB was discovered to be the strict peri-operative dietary restriction. Findings disclosed that the RYGB-induced changes in the incretin hormones (GLP-1 and PYY) possibly played a vital role in the long-term compliance with such major dietary restrictions via central and peripheral mechanisms.