The establishment of obesity medicine as an independent board certification is an example of a subspecialty where lifestyle medicine is incorporated as a foundational therapy for a specific medical condition. This chapter reviews the rationale for creation of obesity medicine as a subspecialty, the developmental process undertaken to establish the American Board of Obesity Medicine, and the critical role of developing a certification process. The review of this experience with the emerging field of obesity medicine serves as an exemplar of how to close knowledge gaps with formal education and certification—actions that need to be optimized in the broader lifestyle medicine discipline.