The procedure entails bypassing the duodenum and the proximal jejunum with a 60 cm non-permeable polymeric sleeve which is attached to the duodenal wall. This sleeve prevents the contact of food with the duodenal wall, thereby re-capitulating one of the major properties of the RYGB operation. With this technique, control of diabetes is accompanied by weight loss, with no need for medications that may cause weight gain / hypoglycemia and may serve to replace or postpone surgery.