JMIR Publications

ABSTRACT

Background:

Obesity is a growing public health concern worldwide, significantly contributing to premature mortality and non-communicable diseases. Weight reduction through lifestyle interventions, including diet and physical activity, is the primary approach to combating obesity, with studies showing that a 5-10% weight loss can notably reduce obesity-related complications. Recently, smartphone applications have emerged as popular tools to aid in weight loss. However, the effectiveness of smartphone-only apps for weight management in overweight/obese patients without comorbidities remains unclear.

Objective:

This meta-analysis aims to evaluate the efficacy of these apps in supporting weight loss and improving body composition in such populations.

Methods:

A systematic review and meta-analysis were conducted following PRISMA guidelines, with a search across databases including PubMed, Scopus, Cochrane Library, and others. The inclusion criteria were randomized controlled trials (RCTs) involving adults (≥18 years) with overweight/obesity (BMI ≥ 25 kg/m²) and assessing the use of smartphone-only applications for weight loss. Studies using additional devices or involving participants with comorbidities were excluded. Data extraction focused on weight loss, BMI, waist circumference, and body fat percentage, and the risk of bias was assessed using the Revised Cochrane Risk-of-bias Tool.

Results:

A total of 11 RCTs with 1,717 participants were included in the meta-analysis. The interventions, lasting between 60 days and 12 months, involved diet and exercise monitoring via smartphone apps. At 4-6 months of follow-up, app-based interventions significantly reduced body weight (SMD = -0.33, 95% CI -0.48, -0.17; P < .0001; I² = 49%) and BMI (MD = -0.76, 95% CI -1.42, -0.10; P = .02). Reductions in body fat percentage were also observed at 3 months (MD = -0.79, 95% CI -1.38, -0.20; P = .009) and between 4-6 months (MD = -0.46, 95% CI -0.71, -0.20; P = .0005). However, no significant effects on waist circumference were noted.

Conclusions:

Smartphone apps demonstrate a modest but statistically significant effect on weight loss and BMI reduction over a 4-6 month period in overweight/obese individuals. The effectiveness of these interventions appears limited beyond 6 months, with a tendency for weight regain. Many apps lack the personalized support necessary to sustain long-term weight loss, contributing to high dropout rates. Future development of weight loss applications should focus on enhanced customization to improve user adherence and long-term outcomes. Clinical Trial: International Prospective Register of Systematic Reviews (PROSPERO) CRD42024570999 https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024570999