Philippov Fast and Disease: Nutritional, Metabolic, and Psychosomatic Dynamics in the Context of Asceticism Introduction: Fasting as an Anthropological and Physiological Phenomenon The Philippov (Rozhdestvensky) Fast is one of the four long-term fasts in the Orthodox tradition, lasting from November 28 to January 6. From a medical and nutritional perspective, it represents a unique example of a long-term, cyclically repeated food restriction with certain qualitative characteristics (refusal of animal products, on certain days — fish and vegetable oil). Studying its impact on the body during illness requires a comprehensive analysis, taking into account not only the biochemistry of nutrition but also the psychoneuroimmune aspects of faith and ritual. Biochemical and Metabolic Aspects of Fasting During Illness Energy balance and protein: The main limitation is the deficiency of high-quality animal protein containing all essential amino acids. For a healthy organism, a short-term deficiency may be compensated for by plant combinations (legumes + grains). However, during illness, the need for protein sharply increases — it is necessary for the synthesis of immunoglobulins, antibodies, and tissue repair. A long-term fast with an unbalanced plant diet may slow down recovery from acute infections, injuries, and after operations. Fat-soluble vitamins and trace elements: Refusal of animal products creates a risk of deficiency in vitamin B12 (critical for blood formation and the nervous system), iron (in heme form, more easily absorbed), calcium, and vitamin D (especially in the absence of fish and dairy products). This may exacerbate conditions related to anemia, osteoporosis, and immune dysfunction. Food fibers and microbiome: A sharp transition to a diet rich in fiber (vegetables, grains, legumes) may cause dyspeptic symptoms in an unprepared person (bloating, gas formation). However, in the long term, this has a beneficial effect on the gut microbiome, which is important ... Read more