Examining Valence-based Effects in Self-Monitoring Feedback Messages

Inclusion Criteria: * Age greater than or equal to 18 years * BMI greater than or equal to 25.0 kg/m2 * Weight less than or equal to 175 kg (due to scale limit) * Own a smartphone compatible with Fitbit (e.g., an Apple iPhone running iOS 16.4 or higher or Android smartphone running Android 11 or higher) with a cellular and data plan Exclusion Criteria: * Weight greater than 175 kg (due to a weight limit of the study-provided scale) * Smartphone device owned deemed incompatible with the Fitbit App * History of bariatric surgery or plans to obtain bariatric surgery during the study period * Current use of weight loss medications, or use of weight loss medications in the 6 months prior to initial pre-screening * Currently participating in a weight-loss program * Weight loss of greater than or equal to 10 lbs in the 6 months prior to initial pre-screening * Physical limitations that prevent walking at a brisk pace for at least 10 minutes without stopping * Use of a pacemaker or other implanted medical device * Currently pregnant * Currently breastfeeding * Less than 1-year post-partum * Plans to become pregnant within the study period * Lack of written confirmation that the potential participant has discussed study participation with their physician if they have been diagnosed with diabetes, hypertension, or has have a history of coronary heart disease * One or more study participants living in the household (enrollment limited to one participant per household) * Medical conditions that contraindicate weight loss or prevent completion of the study (e.g., current diagnosis of cancer or terminal illness, dementia, etc.) * Recent (in the past 6 months) changes in medications that affect weight * Self-reported eating disorder within past 5 years * Unable to complete the 17-week study (due to plans to relocate during the study period, etc.) * Unable or unwilling to provide informed consent * Unable to read English at the 5th grade level * Unwilling to accept random assignment * Unable or unwilling to download the study smartphone application, wear the physical activity monitor, or use the study e-scale * Failure to complete baseline assessment measures * Failure to complete at least 4 out of 6 days of self-monitoring dietary and weight self-monitoring during the behavioral run-in period * Any other condition(s) which, in the opinion of the Principal Investigator, would adversely affect participation in the study