Participants also will be assigned to attend one-on-one "robotic assistance sessions" either early or late in the five-week study. During each robotic assistance session, the participant will speak with the robot about his/her progress with the weight loss program. The robot is programmed to respond to specific issues raised by the participant, but a human operator with thorough knowledge of the weight loss program will be available in case the conversation goes "off script." This human operator can initiate robot behaviors and prompt verbal responses through a text-to-speech interface.