The effectiveness of smartphone applications that target eating in facilitating weight loss at six months and longer: A meta-analysis and bias correction

Background/objectives: Smartphone applications (“apps”) could be cost-effective tools for weight loss that circumvent some of the issues of standard weight-loss interventions. Although numerous weight-loss apps are available, their results have been mixed and their longer-term efficacy remains unclear.Subjects/methods: We conducted a meta-analysis of randomised controlled trials that used apps to target eating behaviour for weight loss in adults. A database search identified 23 studies, including multi-arm studies reporting more than one app-based trial. We meta-analytically (a) compared the amount of weight lost in app-based interventions to waitlists and non-app-based interventions, such as group sessions and self-monitoring, and (b) estimated mean weight loss at six months and longer in app-based interventions.Interventions/methods: We used three-level meta-analytic models which forgo the need to randomly select trials from multi-arm studies. Where publication bias was detected, we applied additional random-effects models and various bias-correction methods.Results: More weight was lost in app-based interventions than on waitlists (mean difference 2.07 kg [95%CI 1.09; 3.05], p < .001, k = 12) and in non-app-based control interventions (mean difference 1.64 kg [95%CI 0.25; 3.03], p = .024, k = 15) at six months. Across all app-based interventions (k = 27), weight loss estimates ranged from 0.63 to 3.87 kg at six months. At longer follow-ups (typically 12 months), mean weight loss was 2.64 kg [95%CI 1.70; 3.57], p < .001, k = 11). Despite high heterogeneity in meta-analytic estimates, we found no significant moderating effects of apps’ or interventions’ features such as calorie counting, social support, involvement of medical workers, or automatic feedback reports.Conclusions: More long-term studies are needed to clarify apps’ effectiveness over time. Smartphone apps could be a cost-effective alternative to traditional behavioural interventions and could help maintain weight loss following surgery or drug treatments.