Lifestyle medicine leverages six pillars—a predominantly plant-based diet, physical activity, sleep, avoiding risky substance, stress management, and social connection. Facilitating behavior change represents the crux of success with each of these pillars. Positive emotions and positive psychology constructs are shown to drive behavior change in the upward spiral theory of lifestyle change. Moreover, positive psychology interventions serve as additional, independent protective health factors. This paper offers a brief review of the empirical evidence for these roles of positive psychology and makes the case for explicitly adding positive psychology to the foundational lifestyle medicine pillars.