Psychophysiology of Fasting

Dr Swami Karmananda Saraswati, MB, BS (Syd.)

Many scientists have sought to explain the underlying mechanism by which fasting therapy corrects abnormal and unbalanced psycho-physiological systems, and restores health so efficiently. Its stabilizing effects on the . nervous system have been measured electrically through brain wave recordings and its effects on the endocrine glands have been traced bio-chemically. Both sets of findings tend to confirm that fasting allows the autonomic systems of the body to function at a relaxed baseline level, free from the erratic and disruptive influences of the nervous system and hormones.

Effects on the brain and nervous system

Suzuki et al. in 1976 studied changes in the brain waves from 262 fasting patients and noted a slowing and synchronization of alpha waves, together with an increased incidence of theta waves.*1 These observations are descriptive of a more relaxed and introspective state of awareness, which is less neurotically preoccupied with the superficial and transitory patterns of thought that characterize the normal waking state. Similar brain wave alterations were recorded in Zen meditators by Kasamatsu and Hirai (1966)*2 and by Banquet (1973) in subjects practising japa yoga.*3 This suggests that fasting and meditation exert similar psycho-physiological influences on the brain and nervous system, perhaps healing psychosomatic complaints and maintaining optimal health and wellbeing by a single common mechanism.

The significant slowing of brain waves suggests that fasting induces a transient slowing down of the central nervous system. It seems plausible that more complex changes in the autonomic nerves and endocrine glands may then occur. An over active autonomic nervous system, which constantly relays abnormal mental and psychic stresses into the physiological systems, produces many psychosomatic symptoms and disease states, Through fasting and meditation these stresses are removed, allowing the mechanisms responsible for blood pressure, respiratory and cardiac rate, gastrointestinal secretion and motility, etc. to revert spontaneously to a more natural level of functioning.

In Suzuki's study, this brain wave phenomenon disappeared upon termination of fasting therapy, and peak EEG frequency and wave configuration returned to a pattern strikingly similar to pre-fasting discharge patterns. However, in a more recent Japanese study of 380 fasting patients*4, where the EEG analysis was more sophisticated, peak frequency decreased significantly at the end of the fasting period, suggesting that a stable new physiological state is created in the post-fasting period. In addition, the overload of fast beta waves observed in the pre-fasting period decreased in the fasting period, and did not reappear again in the same fashion after the recovery phase. As these faster waves have been associated with anxiety, tension, neuroticism and irritation, their disappearance on EEG may be an objective indication that fasting either partially or totally eases these symptoms permanently.

Recently, the metabolic changes induced by fasting have also been investigated. The normal metabolic fuel of the brain is glucose, released into the bloodstream from the digestion of dietary carbohydrates and sugars. The research of G. F. Cahill of Joslin Research Laboratory, Harvard Medical School, USA (1966-1969), revealed that this situation changes dramatically during fasting. As the fast proceeds, the body's stores of carbohydrates in the liver are rapidly exhausted, and the brain's requirements for glucose, its sole fuel, must then be met by non-carbohydrate sources. The new source is the ketone body, derived from the hydrolysis of fat stored in the body's adipose tissues.

It appears that the brain's switch from starch to ketone nutrition works as a strong stressor upon the brain cells, and temporarily places all biological mechanisms in a stress state. This may activate the natural healing power inherent in the human body, thereby bringing about homeostasis, and a return to healthy function.

Effects on the endocrine glands

Disordered function of the network of endocrine glands, with their secretion of abnormal and ill-timed quantities of hormones into the bloodstream, is a potent cause of physiological disruption. In addition, abnormal blood concentrations of gonadal, pituitary, adrenal and thyroid hormones are now recognized to be a major determinant of unhealthy emotional and psychological states, profoundly affecting mental health and wellbeing.

Endocrinologists are able to assess the function of the hypothalamus-pituitary-adrenal axis of glands by measuring the levels of hormone by products found in the urine and blood. In the 1979 Tohoku study, this analysis indicated that the activity of the hypothalamus-pituitary-adrenal axis declines during fasting. This state is very similar to that which occurs immediately after the endocrine glands have been activated by a stress situation. At that time, after the initial burst of secretion, there is a stable or refractory resistance period, during which the capacity of the glands to respond to any new incoming stimuli is severely depressed.

This may provide a welcome period of rest and rehabilitation for the long overburdened physiological and metabolic processes, allowing them to regain the level of basic function from which they have deviated for so long under constant autonomic and endocrine stimulus. During this hiatus, the restoration of function can occur without disruption or interruption. Thus, the initiation of this artificial stress response may be the key by which fasting unlocks the body's own dormant healing energies.


*1. J. Suzuki, Y. Yamauchi, M. Horikawa and S. Yamagata, 'Fasting therapy for psychosomatic diseases with special reference to its indication and therapeutic mechanism', Tohoku J. Exp. Med., 118: 245-259, 1976.

*2. A. Kasamatsu and T. Hirai, 'An electroencephalographic study on Zen meditation (Zazen)', Folia Psychiat. Nenrol. Jap-, 20:315-336, 1966.

*3. J. P. Banquet, 'Spectral analysis of the EEG in meditation', Electroenceph. Clin. Neuro-physiol, 35: 143-15, 1973.

*4. H. Yamamoto, J. Suzuki and Y. Yamauchi, 'Psychophysiological study of fasting therapy', Proc. 12th Eur. Conf. Psychosom. Res., Psychother. Psychosom., 32:229-240, 1979.