In this Mailbag installment of The Observable Unknown, Dr. Juan Carlos Rey of crowscupboard.com responds to listener Priya A. of Seattle, who asks whether ancient fasting rituals were early, intuitive ways of shaping the gut–brain connection. Drawing from modern neurogastroenterology, nutritional neuroscience, and microbiome research, Dr. Rey traces fasting through time - from Upanishadic austerity and monastic silence to the cellular ecologies within us. He revisits the verified work of Mark Mattson (National Institute on Aging), Valter Longo (University of Southern California), and Satchidananda Panda (Salk Institute), alongside cross-cultural rites that discovered metabolic renewal long before molecular biology. Listeners learn how temporary abstinence activates brain-derived neurotrophic factor, regenerates immune function, recalibrates circadian genes, and modulates the microbiome’s chemical symphony of serotonin, dopamine, and GABA. Ancient seekers may have lacked microscopes - but they possessed an embodied intuition that consciousness and digestion are one continuum of rhythm and light. Fasting emerges here not as deprivation but as dialogue - a physiological prayer aligning metabolism, mood, and meaning. Dr. Rey invites the audience to consider hunger as a form of listening: an emptiness through which the body remembers its original harmony. Email reflections or questions to TheObservableUnknown@gmail.com, or text 336-675-5836. Reviews and ratings on Podbean or Apple Podcasts help sustain this global conversation between science, soul, and the unseen. Keywords: fasting, gut-brain axis, microbiome, neuroplasticity, BDNF, circadian rhythm, Valter Longo, Mark Mattson, Satchidananda Panda, psychobiotics, neuroscience, spirituality, The Observable Unknown, Dr Juan Carlos Rey, crowscupboard.