Fasting, Vigil, and Vision
What hunger and sleeplessness do to the senses.
In the Texts
The possessed and the saintly alike fasted, and the manuals prescribe fasting for the exorcist and the patient both, with vigils and prayer through the night, before the rite; the visions that came in the small hours were taken as the demon’s or the saint’s.
What Medicine Makes of It
Prolonged fasting lowers blood sugar and, after a few days, floods the brain with ketones; sleep deprivation past a night or two brings hallucination in most people, and the two together, with solitude and expectation, reliably produce visions, as every tradition of the vision quest has known. Ancel Keys’s Minnesota starvation experiment of 1944 recorded the depression, the obsession, and the strangeness of mind that semi-starvation brings in healthy men. Rudolph Bell’s Holy Anorexia (1985) read the fasting saints of Italy beside the anorexic patients of the clinic and found the same physiology under different meanings.
The Evidence
- Keys’s Minnesota experiment (1944–45) kept 36 men at half rations for six months: depression, irritability, obsession with food, loss of interest in sex, and in some, psychiatric breakdown, in men chosen for their stability.
- A single night without sleep produces perceptual distortions; by 72 hours most subjects hallucinate (Waters et al., 2018, reviewing 21 studies), and the content is what the subject expects.
- Ketosis after a few days of fasting raises the brain’s GABA and changes mood; medieval visionaries fasted for weeks before the great visions (Bynum, 1987).
- Bell (1985) read 261 Italian holy women from 1200 to the present and found the pattern of anorexia nervosa in half: the refusal of food as control, the euphoria of fasting, the visions in extremity.
- The “vision quest” of the Plains and the incubatio of Epidaurus used the same means, fasting, solitude, vigil, and expectation, to the same reliable result.
Where They Part
The manuals are right that fasting prepares the mind for the rite; the clinic says it does so by weakening the mind’s hold on what is outside it. The preparation and the affliction are the same thing seen from two sides.
In the Materia Medica
Sources
- Keys, A., et al. (1950). The Biology of Human Starvation. University of Minnesota Press.
- Bell, R. M. (1985). Holy Anorexia. University of Chicago Press.
- Waters, F., et al. (2018). “Severe sleep deprivation causes hallucinations.” Frontiers in Psychiatry 9.
Historical and interpretive; not medical advice.