Methods and devices for maintaining a space-occupying device in a fixed relationship relative to a patient's stomach by manipulation of the stomach. In one variation, two or more regions of the stomach wall are brought into approximation with one another and secured together in a manner that secures a space-occupying device within the stomach of the patient. In another variation, two or more regions of the stomach wall are wrapped around a space-occupying device to maintain the position of the space-occupying device relative to the stomach wall. In another variation, a system having a space-occupying member and a locking member capable holding the space-occupying member against the inner wall of the stomach are provided. In a further variation, a pouch is created within the stomach that receives and retains a space-occupying device.