This project explores standards of obesity medical care by reviewing the continuing medical education (CME) curricula that aspiring specialists must master for certification by the American Board of Obesity Medicine. I will pay close attention to the ways that specialists in weight-management medicine theorize contested topics like ‘natural’ hunger, metabolic homeostasis, and human evolution in a clinical approach to behavioral intervention called “Acceptance-based Behavioral Therapy” (ABT). How do clinicians teach patients to respond to their “thrifty genes,” or the human body’s genetic tendency towards fat accumulation? What affective relationships to food, eating, and the human body are invoked by the practices of medically supervised weight loss? How are these affective relationships justified by ABT’s interpretation of evolutionary history and inherited taste? Exploring these questions will illuminate the degree to which weight-centric behavioral interventions like ABT depend on paleofantasy for epistemic legitimacy, moral strength, and patient motivation.