In a final salvo of publications, Kant grappled with “dietetics” as a conduit to the art of living. He endorses a dietetical regimen that is universalist in form but agnostic in content in that he does not prescribe specific lifestyle choices. Kant’s remarks were developed in exchange with Christoph Wilhelm Hufeland, the premier physician of the German-speaking world of the day. Hufeland had just published The Art of Prolonging Life, a treatise on “rational medicine,” for which he later coined the term “macrobiotic.” The medical primer became a best-seller and was translated into all of the major European languages. What is more, it presaged today’s personal development industry with its staunchly self-empowering ethos and entrenched self-help credo. While global revenue from book sales has been steadily declining, one rubric is flourishing: “self-improvement” literature enjoys an expanding readership with global market volume expected to reach 14 billion US-dollars by 2025. The universalist premises driving this commercial sector were laid out at the end of the 18th century in the Kant/Hufeland intermezzo. The dietetical precepts they endorse still inform the applied universalisms of present-day anti-aging aspirations from intermittent fasting to transhumanism. But their positions are starkly at odds with respect to the individuation of selfhood.