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

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

Design: 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."

Methods: 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.