Anorexia Nervosa is a life-threatening psychiatric condition that is typically associated with food restriction and may also be associated with excessive Physical Activity (PA), including fidgeting. Therefore, patients may benefit from interventions aimed at reducing excessive physical activity. We developed a prototype of a shoe-based wireless activity monitoring and biofeedback system (TWEETY) that provides audiovisual feedback on an android phone. Tweety is based on SmartShoe with built in pressure sensors and accelerometers. The system monitors daily activities, characterized as sitting, standing, walking, and provides multiple levels of feedback when the subject is sitting while fidgeting. The sensor data are wirelessly delivered to a remote server that runs a pattern recognition algorithm and sends the feedback response to the user's phone. The user-interface uses a sprite of a canary bird to provide multiple levels of feedback. The system was tested on 2 healthy subjects. Preliminary results show that the activity monitoring and biofeedback system has a high level of accuracy and may be suitable for helping Anorexia Nervosa patients' rehabilitation.