Health Behavior Theories in Diet Apps

iPhone apps are being used to promote healthier diets. The purpose of this study was to evaluate the extent to which diet apps' content was guided by health behavior theory in their design and user interface. This study consisted of 58 diet apps from iTunes' Health & Fitness category. Coders downloaded the apps and rated their inclusion of theory. Scores ranged from 0 to 26 on a 100-point scale. Most apps were theory deficient and provided just general information/assistance. An opportunity exists for health behavior change experts to partner with app developers to incorporate health behavior theories into the development of individually tailored apps.