Abandonment of wearable fitness trackers continues to be an ongoing issue. Literature has compiled many reasons; however, the roles of data literacy and data visualization literacy have been underexplored. Two qualitative studies, an online survey and in depth semi-structured interviews investigated whether insufficient data interpretation is a barrier to sustained tracker use. Results found that users may overestimate their literacy levels potentially leading them to misinterpret health data, and better support from designers and professionals is warranted. In particular, mandatory tutorials and assessments unlocking data are explored. Interaction with smart shorts, smart insoles, and accompanying data provided insight on who might adopt newer wearables, who could benefit, and how to design a better onboarding user experience. Recommendations for better use of wearable technology to address physical inactivity and obesity, as well as suggestions to support literacies are presented that the HCI community can use to move the field forward.