Fasting

Fasts differ so much in their rules that treating them as one practice can mislead. What varies is the substance, the duration, the intensity and who is excused.

Ramadan is a daytime fast: no food, no drink of any kind including water, no smoking and no sexual activity from first light to sunset, for a lunar month, broken each evening and resumed before dawn. Because the Islamic calendar is lunar, Ramadan moves through the seasons, so a summer Ramadan at high latitude can mean nineteen hours without water. The exempt are named rather than left to conscience: the ill, the travelling, the pregnant, the nursing, the menstruating, the elderly and the young, with make-up days later or a payment for the poor instead.

Yom Kippur is a full twenty-five hours without food or water, and adds prohibitions on washing, anointing, leather shoes and sex. Judaism keeps several other fast days, most of them from dawn to nightfall only.

Christian fasting has become the loosest of the major forms. The Lenten discipline of the Latin church now amounts to abstaining from meat on Fridays and two days of reduced eating, a very considerable relaxation from the medieval rule. Orthodox fasting is far more demanding and is mainly a matter of exclusion rather than quantity: no meat, dairy, eggs, fish, oil or wine on the strictest days, across something approaching half the year.

Indian traditions more often restrict category than amount: a vow to take one meal only, or fruit only, or nothing grown underground, kept on named days of the lunar month. The Buddhist monastic rule against eating after midday is a permanent low-grade fast rather than a seasonal one, and it changes the shape of a life more than an annual month does.

The reasons traditions give for fasting sort into a small number of arguments, and they do not sit comfortably together.

The penitential argument treats hunger as a payment, or as the outward sign of sorrow. It runs strongly through Christian and Jewish practice, where fasting attaches to atonement and to mourning, and it is the reading most exposed to the objection that it makes God someone who requires suffering.

The ascetic argument treats appetite itself as the thing to be trained. If the will can refuse food, which is the least negotiable of wants, it can refuse anything. This is the argument of monastic Christianity, of Jain and Hindu asceticism, and of the Buddhist rule on eating hours.

The solidarity argument is prominent in modern Muslim and Christian teaching: the fast gives the comfortable a short taste of what the poor experience without choosing it. Ramadan is bound to a sharp annual rise in charitable giving, which makes the connection concrete rather than rhetorical.

The clarifying argument holds that a lightened body sharpens prayer and perception, and it recurs in mystical writing across traditions with little regard for what else those traditions believe.

These are different claims and they imply different practices. A fast undertaken for solidarity has no reason to be hidden and every reason to be visible. A fast undertaken as discipline has good reason to be concealed, and several traditions instruct exactly that: the gospel injunction to wash the face and anoint the head so that the fasting is not seen is a direct attack on fasting as display, and the fact that it needed saying tells you what was happening.

Fasting has real physiological consequences, and the traditions are less naive about this than outsiders often assume.

Every large tradition excuses the vulnerable, and not grudgingly. Islamic law treats fasting while ill or pregnant as wrong rather than merely permitted. Jewish law requires eating on the Day of Atonement where life is at risk, and a rabbi will rule on it if asked. The clinical literature on Ramadan is substantial and largely reassuring for healthy adults, while identifying genuine risks for people with diabetes, for those on medication schedules that assume regular food, and for outdoor workers in heat. Medical bodies in Muslim-majority countries publish guidance jointly with religious authorities, which is a useful instance of the two operating together rather than against one another.

The genuinely difficult cases sit at the end of life. The Jain vow of sallekhana ends in death by design, and is defended by its practitioners as the opposite of suicide precisely because it excludes despair and appetite; Indian courts have suspended a ruling against it and never resolved the question. Christian ascetic tradition contains extreme fasting, and historians of late medieval women's piety have argued at length over how far the recorded cases overlap with what would now be diagnosed as an eating disorder. That argument cannot be settled from the sources, and it should not be closed in either direction by assertion, neither by pathologising the women involved nor by refusing to consider it.

There is also a secular inheritance. Intermittent fasting and extended water fasts are now marketed as health protocols with the religious frame removed. They are not the same practice. The traditional forms are communal, calendrical and bounded by rules somebody else wrote, and that changes both their psychology and their risks.