Transoral obesity treatment devices and related methods for operation thereof are described which occupy space within a stomach and/or stimulate the stomach wall. The transoral obesity treatment devices and related methods are intended to assist a patient in maintaining a healthy body weight. Features of the devices include insertion transorally and without invasive surgery, without associated patient risks of invasive surgery, and without substantial patient discomfort. The life span of these devices may be material-dependent upon long-term survivability within an acidic stomach, but is intended to last one year or longer. The devices have the capacity to vary in size and are desirably self-actuating in that they change shape and/or volume using internal motors or actuators. The changing character of the devices helps prevent the persons stomach from compensating for the implant, such as sometimes happens with static intragastric devices.