Practices depend on individual temperament and social conditions of the time.
Reprinted from The Jewish Religion: A Companion, published by Oxford University Press.
As in other religions there are ascetic trends in Judaism. At the end of tractate Kiddushin in the Palestinian Talmud, the saying is found that a man will be obliged to render account before his Maker in the Hereafter for every legitimate pleasure he denied himself. But it is absurd to quote this stray saying, as is often done, to show that Judaism is opposed to any kind of asceticism. As we might have expected, the Talmud contains statements both in favor of asceticism and against the tendency.
There is, for instance, a debate among the Talmudic teachers on whether one who fasts is a sinner or a holy man. The debate depends on how the biblical institution of the Nazirite is understood. One teacher holds that the Nazirite is a holy man, and this teacher argues that if the Nazirite, who only took a vow to abstain from drinking wine, is a holy man, then the one who fasts and denies himself all food and drink is a fortiori a holy man. The other teacher holds that the Nazirite should be seen as a sinner in that he rejects God's gift of wine, and this teacher holds that one who denies himself all food and drink is an even greater sinner.
The truth is that a good deal depends on individual temperament and the social conditions of the time. Teachers living in a dissolute age will try to redress the balance by advocating the ascetic ideal. (It has been said that Rabbis always appear to live in dissolute ages!) And religious people who feel themselves tempted to overindulgence will naturally be moved to compensate for it by a regimen of abstinence. Judaism is no stranger to these conflicting tendencies and it is ridiculous to draw any neat distinctions between the so-called sane attitude of Judaism and the unbalanced hatred of the body supposedly prevalent in other religions such as Christianity.
In the Middle Ages, Maimonides' advocacy of the golden mean--a man should avoid extremes; he should not be a glutton and wear ostentatious clothes nor should he starve himself and dress in rags---was offset by the teachings of the German saints who went so far as to mortify the flesh by such practices as rolling naked in the snow in winter and allowing themselves to be stung by bees in summer after smearing their naked bodies with honey in order to invite the attention of the bees.
The contention of the historian F. Baer that the German saints were influenced by Christian monasticism cannot be dismissed, but this only goes to show how precarious it is to speak of a normative Judaism expressing itself in monolithic terms throughout its history.
If the Germans were influenced by Christian trends in their society, Maimonides was influenced by the Greek ideal of a harmonious life which had come to him from his Islamic background. The student of the Torah in Rabbinic times was especially encouraged to lead a life of self-denial in the pursuit of his aim. The advice to the student given in Ethics of the Fathers (6. 4) is: "This is the way of the Torah. You must eat bread with salt and drink water by measure, and you must sleep on the ground and live a life of pain while you toil in the Torah." A similar saying in a late midrash has it that the student, instead of praying that the words of the Torah should enter his innards, should pray that food and drink should not enter his innards.