A device for inducing weight loss in a patient includes a tubular prosthesis positionable at the gastro-esophageal junction region, preferably below the z-line. In a method for inducing weight loss, the prosthesis is placed such that an opening at its proximal end receives masticated food from the esophagus, and such that the masticated food passes through the pouch and into the stomach via an opening in its distal end.