Effectiveness of a Smartphone Application for Weight Loss Compared With Usual Care in Overweight Primary Care Patients A Randomized, Controlled Trial

Background: Many smartphone applications (apps) for weight loss are available, but little is known about their effectiveness. Objective: To evaluate the effect of introducing primary care patients to a free smartphone app for weight loss. Design: Randomized, controlled trial. (ClinicalTrials.gov: NCT01650337) Setting: 2 academic primary care clinics. Patients: 212 primary care patients with body mass index of 25 kg/m(2) or greater. Intervention: 6 months of usual care without (n = 107) or with (n = 105) assistance in downloading the MyFitnessPal app (MyFitnessPal). Measurements: Weight loss at 6 months (primary outcome) and changes in systolic blood pressure and behaviors, frequency of app use, and satisfaction (secondary outcomes). Results: After 6 months, weight change was minimal, with no difference between groups (mean between-group difference, -0.30 kg [95% CI, -1.50 to 0.95 kg]; P = 0.63). Change in systolic blood pressure also did not differ between groups (mean between-group difference, -1.7 mm Hg [CI, -7.1 to 3.8 mm Hg]; P = 0.55). Compared with patients in the control group, those in the intervention group increased use of a personal calorie goal (mean between-group difference, 2.0 d/wk [CI, 1.1 to 2.9 d/wk]; P < 0.001), although other self-reported behaviors did not differ between groups. Most users reported high satisfaction with MyFitnessPal, but logins decreased sharply after the first month. Limitations: Despite being blinded to the name of the app, 14 control group participants (13%) used MyFitnessPal. In addition, 32% of intervention group participants and 19% of control group participants were lost to follow-up at 6 months. The app was given to patients by research assistants, not by physicians. Conclusion: Smartphone apps for weight loss may be useful for persons who are ready to self-monitor calories, but introducing a smartphone app is unlikely to produce substantial weight change for most patients.