Adiposity-based chronic disease (ABCD) is a medically actionable diagnostic term that conceptualizes and entrains complications-centric care since it indicates what is being treated (adiposity-based: abnormalities in the mass, distribution, and function of adipose tissue) and why it is being treated (chronic disease: prevention and treatment of complications that impair health). Additionally, ABCD provides a framework for primordial, primary, secondary, and tertiary disease treatment and prevention. This chapter explains the ABCD conceptual model, its pathophysiology, and modalities for prevention and treatment, with lifestyle therapy being key at each phase of the progression of this chronic disease. This chapter also discusses the implications of ABCD as a diagnostic term regarding complications-centric care and patient evaluation, disease coding systems, and the development of a rational chronic disease care model.