 This study includes a behavioral weight loss program delivered entirely via on online social network. The weight loss intervention is based on the Diabetes Prevention Program DPP, an evidence-based weight loss program focused on lifestyle changes. The goals for the intervention are 175 minutes of moderate physical activity per week and an overall weight loss of 7. Each participant will get an individualized calorie goal that would facilitate a 1-2 lbs. weight loss weekly. Participants will be connected to one another via Facebook and receive behavioral counseling via posts from coaches who are present on the network daily. Participants will track their diet and exercise via a free commercial mobile app. Participants will be assigned to either a Facebook group allowing the invite of friends or a Facebook group including only study participants. If they are assigned to the group including their friends, they have the opportunity to invite their friends to participate in the weight loss group if they are interested in losing weight as well. Friends of friends may also be invited. They will not have a limit as to how many friends they can invite. Facebook has a feature which will allow anyone to invite friends into a group. The friends that are invited will not undergo the same procedures as the FBfriends study participants, but we will provide them with a factsheet and collect minimal information from them. Feasibility outcomes include engagement frequency of posts, likes, and comments and number of completed days of tracking posted retention, acceptability, and weight loss. Post intervention focus groups will gather feedback on the program. 