Disclosed is a swallowable self-expanding gastric space occupying device and related methods of making and using the device to control obesity. The device has a membrane through which gastric liquid can pass, wherein the membrane provides an enclosure volume separated from the gastric environment by the membrane. A plurality of self-expanding components is contained in the enclosure volume, so that the components expand in volume upon contact with the gastric fluid, thereby expanding the device from an unexpanded volume to an expanded volume. Composite membranes provide the ability to precisely control how and when the membrane degrades in the stomach, to release the self-expanding components from the enclosure and to ensure that the released pieces are sufficiently small to not obstruct any portion of the gastro-intestinal system.
