The following report outlines a design project about self-tracking, a food diary app, with the goal of encouraging young adults to record and understand their eating behaviour. The project was executed for the graduation course, as part of the Master’s program at the Faculty of Industrial Design Engineering at TU Delft. This report begins with an introduction to the project, including the background of self-tracking, assignment and approach. The design will focus on young adults who live alone and work full time. Next, from the literature research and user research, insights were drawn on the current experience of using food-tracking tools. Self-Determination Theory and Gamification Theory were applied to help with analyzing the user characteristics and contextual factors. Based on research, the design goal was formed: Engaging young adults who live alone and work full time to record and better understand their eating behaviour. Users should feel supported and competent when interacting with the design, reporting the food-related data without pressure and unpleasant feeling, and at the same, keep engaged through using. Based on this goal, I next explored the solution space, narrowing it down to three possible concept directions that would take the redesign in three different extreme directions. Evaluations for all three tests were conducted with seven participants. The results showed that a combination of various elements from the three concepts should be used for the redesign in order to optimize the user experience. Next, after a redesign workshop and a cognitive walkthrough, the final concept was detailed and a high-fidelity prototype was created. This prototype was evaluated in a user test with six participants. The results demonstrated the strength of many of the design decisions, while also showing areas of improvement; such as the need to better guide the user when choosing their weekly goal. The recommendations and limitations were discussed as well in the end.