Type 2 diabetes mellitus (T2DM) can be prevented through weight loss and increased physical activity, yet its prevalence continues to rise. This trend may be due in part to low rates of participation in evidence-based lifestyle change programs such as the Diabetes Prevention Program (DPP). New strategies are needed to promote healthy behaviors among individuals at risk for T2DM, and mobile health technologies may be an effective and scalable approach to achieve this. One promising tool is JOOL Health, a mobile phone-based application that leverages principles from Self-Determination Theory to help individuals understand how certain behaviors (e.g. sleep, diet, physical activity) influence their ability to pursue their core values and purpose in life. Through personalized messaging and feedback, JOOL Health aims to increase autonomous motivation, a form of motivation closely associated with the initiation and maintenance of healthy behaviors.