A gastrointestinal implant device is positioned in a patient's small intestine or rectum and produces an outward force that itself produces a distension signal which is a therapeutically useful neural or humoral signal that evokes satiogenic or weight loss effects by itself. The device may advantageously be placed in the duodenum adjacent the pylorus or in the jejunum, ileum or rectum. The distension signals may amplify chemosensory or mechanosensory signals such as enteroendocrine secretions within the patient. The device may be a mesh and include a low material density that allows for unrestricted chyme absorption within the small intestine and unrestricted chyme flow through the gastrointestinal system. A method includes inserting the device into the patient then either retrieving the device after treatment is complete or allowing a device formed of a biodegradable material to degrade in time after treatment is complete.