Feature Availability Comparison in Free and Paid Versions of Popular Smartphone Weight Management Applications

Characterize capabilities of nutrition applications (apps) for weight management and associations between features, ratings, and app installations.

Calorie tracking apps with weight management as a primary outcome were selected from the Apple App Store and Google Play Store using keywords "diet" and "weight loss."

Reviewers assessed free and upgraded versions of nutrition apps (n = 15) for features within 4 categories: (1) dietary intake, (2) anthropometrics, (3) physical activity, and (4) behavior change strategies.

Presence of specific app features, app ratings, and app installations.

Descriptive statistics of free and paid app versions. Spearman rank-order correlations were used to determine associations between feature inclusion, app ratings, and installations.

The apps had the greatest number of features in the dietary intake category. Additional dietary intake features were those most likely obtained through a subscription purchase. Behavior change content was absent from most apps. The macronutrient adjustment feature was strongly associated with average app ratings (r_s = 0.74; P < 0.002) and with subscription costs (r_s = 0.60; P < 0.019).

This study found most nutrition apps possess an abundance of features dedicated to dietary intake, anthropometric, and physical activity tracking while also being notably devoid of behavior change content features.