Statistical analysis
The primary analysis population was all study participants providing weight data after 12 weeks of intervention ( = completers analysis). Integrity and plausibility checks were performed. Absolute and relative frequency, means, and standard deviations were calculated. For comparison of baseline characteristics between the groups, a Two sample For missing data on the primary outcome, last observation-carried forward (LOCF) imputation method was conducted. For the LOCF analysis after 12 weeks, the last weight tracked by the app was used as the last observation if measured weight was missing after 12 weeks. For the LOCF analysis after 24 weeks, the last measured body weight at the study centre and/or the last tracked weight by the app (self-reported) was used.