JMIR Publications

ABSTRACT

Background:

Obesity is a major global health concern, and scalable digital solutions are urgently needed. While digital lifestyle interventions (DLSIs) have shown promise, prior meta-analyses often included hybrid formats with human support, limiting insights into the effectiveness of fully digital interventions.

Objective:

This study aimed to evaluate the independent effects of standalone DLSIs—defined as interventions delivered exclusively via digital platforms without in-person or adjunctive support—on anthropometric and dietary outcomes in adults with overweight or obesity.

Methods:

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) assessing standalone DLSIs for adults. Five databases (MEDLINE, Embase, PsycINFO, Web of Science, Cochrane Library) were searched through May 16, 2025. Nineteen RCTs were included. Random-effects meta-analyses estimated standardized mean differences (SMDs). Risk of bias was assessed using the Cochrane Risk of Bias 2 tool. Meta-regressions and sensitivity analyses were performed. PROSPERO registration: CRD420251053974.

Results:

Standalone DLSIs significantly improved anthropometric outcomes (SMD 0.24; 95% CI: 0.13–0.36; P<.001; high-certainty) and dietary outcomes (SMD 0.27; 95% CI: 0.07–0.46; P<.01; moderate-certainty). Stronger effects were observed for interventions targeting both diet and physical activity (SMD 0.28) and when compared to waitlist controls (SMD 0.58). Dietary improvements emerged only in programs longer than 12 weeks. Retention positively moderated effect sizes.

Conclusions:

Standalone DLSIs offer scalable, cost-effective strategies for weight and dietary behavior management. Future studies should explore long-term effects, personalization features, and strategies to enhance engagement.