Anorexia nervosa (AN) is a severe, enduring, and often treatment-refractory eating disorder. We hypothesize that abnormal gut-brain signaling underlies the fear of eating and interoceptive dysregulation in AN, serving to maintain the illness. Using a novel ingestible vibrating capsule to probe gut mechanosensation, combined with EEG and computational modeling, we are characterizing gut-brain phenotypes and evaluating potential biomarkers of illness and treatment response.