This document describes the design of a mobile application called Vittles that aims to help users achieve a healthier lifestyle and lose weight. It discusses important risk factors related to illness such as diet, physical activity, and sedentary behavior. The document then outlines the design process using rapid prototyping with multiple iterations of paper and digital prototypes that were evaluated with users. Key features of the app design include easy input of food/activity diaries, setting goals, social connections, and gamification elements to motivate users. The final result is a mobile application that provides feedback and suggestions to help users develop healthier habits.