Impeccable Metabolic Maneuvers Upbring Natural Immunity To You [IMMUNITY]. Homeostatic competence of human body is an output of meticulous and interdependent/integrated/impeccable metabolic functions to resist or overcome diseases and facilitate a lengthy lifespan along the healthy ageing trajectory. Principles of homeostasis are seldom employed in the clinical applications. Perhaps this has led to almost an irreparable derailment of ethics and core competence of medical profession. Ivan Dominic Illich emphasized his criticisms on iatrogenesis and argued that modern medicine had hubristically taken on a mission to eradicate pain, sickness, even death but expropriated the autonomous power of humans to cope with their ailments. It is also quite obvious that the medical profession has failed to learn about ‘healthy individuals’ elaborately. Healthy individuals possess quintessential epigenetic efficiency and homeostatic competence built through several years of disciplined lifestyle, and especially their fitness characteristics are incomparably superior to individuals who never or rarely display propensity to improve their health standards. The disastrous perception of Immunology that ‘Best Homeostasis’ and ‘Worst Allostasis’ are same, hence all the individuals regardless of their health status are equally a potential source of disease transmission during an infectious disease outbreak, has caused severe disruption in various aspects of human life across the globe. Even the healthiest/fittest athletes and outstanding exercisers could asymptomatically transmit an infection to unhealthy people [who led an unhealthy lifestyle] whose disease could be anywhere in the allostasis spectrum ranging from early-stage co-morbidities to severe functional deterioration? Under the aegis of homeostasis and non-specific antibodies [Secretory IgA], a long-lasting Natural Immunity [NI] should be possible excluding the need of ‘specific antibodies’. Expanded Trained Immunity [ETI] proposed by Cassone has been found not only in innate immune system but also in nonimmune cells [both cells of hematopoietic and nonhematopoietic origin] associated with immunological memories from previous microbial encounters. Interesting discoveries about NI and ETI could emerge if they are linked with homeostasis and allostasis to develop objective immunologic tests to differentiate the healthy and unhealthy individuals, and enhance the clarity of immunology. Exercises are strongly linked to immunity; thus, measurements of exercise performance standards could accurately reveal the status of NI of the individuals if exercise performance data are systematically interpreted and correlated with immunologic function. Exercise performance data can be gathered using easily accessible non-invasive inexpensive tools. From the perspectives of homeostasis, we may not have distinct departments in the body to curb/defeat immunological or other non-immunological diseases, but any disease could be a threat to recovery to pre-existing conditions or even survival, if the homeostatic functions are impaired by iatrogenesis. KEYWORDS: Homeostasis, Innate Immunity, Adaptive Immunity, Exercise, Epigenetics, Trained Immunity, Secretory IgA, Allostasis, Immunosenescence, Iatrogenesis.