2.6. Follow-Up Phase (Maintenance). To explore the potential for maintenance of healthy behavior changes, the study included a 17-week follow-up phase. Immediately after the intervention phase, participants were informed that attainment of diet and activity targets was no longer required; payment was now contingent solely upon recording and transmitting handheld data on a predetermined schedule. This follow-up phase in this study is analogous to the “free choice periods” included in many experiments on rewards and undermining, wherein activity is considered an indicator of intrinsic or autonomous motivation (i.e., “free-choice behavior”). Recording was required daily for the first week following treatment, for three consecutive days in posttreatment weeks two and three, biweekly for the next six weeks, then monthly until the final follow-up. Participants could earn incrementally larger financial incentives (from $30 to $80) for uploading data during consecutive followups. All recording-contingent incentives were received at the end of follow-up.