Impacts of Behavioral Compliance on Weight-Loss and Metabolic Profile in a Smartphone App-Based Lifestyle Intervention or Plus Dietitian Supporting: A Randomized and Controlled Trial Among Chinese

Mobile health technologies provided innovative solutions for lifestyle interventions and offered reliable methods to evaluate behavioral phenotypes during such interventions. To systematically quantify the impacts of behavioral compliance on weight-loss and metabolic profiles during lifestyle intervention, a total of 395 Chinese adults with overweight/obesity (BMI >= 24 kg/m(2)) or central obesity (waistline >= 90 cm for men or >= 80 cm for women) were randomly assigned to a smartphone app-based arm (SAA, n = 197) or smartphone app plus dietitian arm (SADA, n = 198) for 6 months. Compliance scores (0-5) were determined based on fulfilling five behavioral tasks: completing online courses, wearing a smart band, and recording weight, food intake, and blood pressure. SADA had greater weight-loss (- 4.94% vs. - 2.28%, p < 0.001) and lower triglyceride, but higher HDL-C levels (both p < 0.05) than SAA after six months. Between-group weight-loss differences were attenuated at compliance scores >= 3 (SADA: - 6.30% vs. SAA: - 4.79%, p = 0.07). Mediation analysis suggested that compliance scores explained approximately 30% of the additional weight loss in the SADA (p < 0.001), and self-weighing was the primary mediator (p < 0.05). Higher educational levels, greater initial weight loss, self-perceived simplicity, and satisfaction with the program were potential determinants of intervention compliance. Overall, the superior weight loss and metabolic improvements in the SADA group could be mediated by behavioral compliance, which was possibly influenced by some demographic and intervention response features. Our findings highlighted the roles of behavioral phenotypes and adherence in app-based lifestyle interventions, and added evidence for the future development of more precise strategies in long-term weight management.