OneNote Meal: A Photo-Based Diary Study for Reflective Meal Tracking.

When a self-monitoring tool is used to enhance behavior awareness, the tool should afford reflection by design. This work examines the "valence of meal" (i.e., healthy versus unhealthy meal) as a means to support reflection on a person's diet in photo-based meal tracking. To study the effect of imposing valence on meal tracking, we designed two conditions-one focusing on capturing healthy meals, the other capturing unhealthy meals-and conducted a between-subjects diary study with 22 college students over four weeks. According to their group assignment, participants tracked only healthy or unhealthy meals by taking photos and rationalizing in texts why their meals were particularly healthy or unhealthy. We found that participants in both groups became more aware of their diet, but the valence of meal influenced them differently regarding their meal assessment, self-reflection, and food choice intention. We discuss ways to leverage valence in designing reflective meal tracking systems.