MapTrek is a mobile-phone-based web app that allows participants to take a virtual walk in interesting locations around the world while tracking their progress against the progress of other veterans on an interactive map. Steps are counted using a commercially available triaxial accelerometer (e.g. Fitbit), and users see their own updated progress overlaid on Google Maps, with Google Maps features (e.g. zooming, street view, etc.) available. The objective is to report activity levels in the virtual environment to veterans, thereby encouraging them first, to walk more every day, and second, to maintain these new increased levels of physical activity.

All consented participants will be provided with a Fitbit and instructed to wear it all day for the next 9 weeks. This process should take approximately 15 to 45 minutes, depending on group assignment.

This, plus an exit survey and 3-month follow-up survey(given via text message or phone call, whichever the participant prefers), will be the extent of the participation in the control group.

Members of the intervention group will be instructed on how to use MapTrek, the virtual walking race. Data collected during the first week from the Fitbit will be used to compute baseline activity level. This baseline data will be used to place participants into an appropriate initial race group. Participants are placed into race groups with other individuals who are active at a similar level, so that groups will be competitive.

Each virtual walking race will begin on Monday and end on Sunday. Depending on each veteran's performance each week, group assignment may change. Participants will compete in 8 week-long races over the course of the study.

For each race, the participants will receive 2-4 text messages each day including a daily status report and a link to the current race. The participants will also periodically receive challenge text messages. If participants accept a challenge and meet it, they will be awarded bonus steps to help move them along the route in the race.

To win a race, participants must be the first to cross the finish line on the route for the week. There is a leaderboard within MapTrek that helps participants determine their standings within each race. Participants are allowed to choose a screen name to show on the leaderboard so that they may remain anonymous if desired.

For all participants, the investigators will collect first and last name and the last 4 digits of the participant's Social Security Number for consent documentation purposes and to look the person up in the VA medical record (CPRS). The following information will be collected from CPRS at baseline: age, sex, race, marital status, height, weight, body mass index, blood pressure, zip code, and current medications. Height, weight, body mass index, and blood pressure values will be collected again at the 9 week and 3 month follow ups. The following information will be collected from the MOVE! participation records at baseline: date enrolled in MOVE! program, number of MOVE! classes attended, weight when enrolled in the MOVE! program.

At the end of the 9 weeks of participation, participants will be contacted to complete an exit survey either via text message or phone call, whichever was stated as the preferred method at enrollment. This will take approximately 10 minutes to complete.

3 months after the study ends, the participants will be contacted to complete a 3-month follow-up survey either via text message or phone call, whichever was stated as the preferred method at enrollment. This will take approximately 10 minutes to complete.

Participants who do not respond will be contacted via text message and phone call up to 3 times. If participants still cannot be reached they will be considered lost to followup.

Inclusion Criteria:

• At least 18 years old
• Be comfortable speaking and reading in English
• Have a BMI of at least 25
• Have a smartphone with texting and internet capabilities
• Be willing to download the Fitbit app onto their phone
• Must be a VA patient

Exclusion Criteria:

• Pregnancy
• Active mental health conditions that prevent them from providing own consent