Sharing Digital Self-Monitoring Data With Others to Enhance Long-Term Weight Loss

If an index participant is randomized to have Coach Share ON, the coach will have continuous access to objective, real-time, detailed device data, and address data directly in all individual interactions with index participants (groups, individual weigh-ins, phone calls, texts), conveying that they are closely monitoring progress.

If Group Share is ON, participants in a given LM group will view and respond to aspects of each other's self-monitoring device data in their small-group text messages. Each small group participant's data will be highlighted one day of the month, and content from the Group Share Off message library also will be sent.

Index participants who are randomized to have Friend/Family Share ON will give their friend or family member access to their self-monitoring data. Text messages sent by the program bot, which includes the index participant and friend/family member, will use a similar format as described in Group Share ON. The friend or family member will be trained to respond to data in ways that enhance the participant's motivation and self-regulation.

Among index participants who are randomized to have Coach Share OFF, the coach will have no access to their device data. Index participants will be explicitly told their coach does not have data access. During groups and phone calls, the participant will self-report progress, and goal setting will be based on that self-report. Text messages from the coach will be personalized in the OFF condition, as they are when coach data sharing is ON, though these messages will not be informed by device data. Instead, text messages will provide a reminder of key goals and strategies discussed in the previous phone call and provide encouragement for participant efforts.

Among index participants randomized to have Group Share OFF, supportive accountability will not be the target of participant interactions and no data will be shared with LM program peers. Instead, once weekly prompts for small group text exchanges will encourage index participants to provide social support (primarily of the informational type) to each other. Index participants will be explicitly told that they should not include information on goal progress such as weight change or minutes of PA.

If an index participant is randomized to Friend/Family Share OFF, the text messages from the bot will prompt the participant and friend/family member to communicate about the LM program; those messages will be standardized, except for names, and will not be tailored to index participant progress. Index participants will be instructed to refrain from sharing any device data with friends or family members.

Standard Behavioral Weight Loss Treatment (remotely delivered)