Long before cooking shows and diet fads, many ancient civilizations understood this balance. The Greeks, for example, worried that excessive consumption would disrupt the four humors constituting the human body. They, like the ancient Buddhist and Confucian traditions, encouraged moderation as the golden mean. Judaism, Christianity and Islam added to those arguments theological overtones: eating too little could be as spiritually damning as eating too much.

The prophet Isaiah, for example, inveighed against the Israelites for vainly fasting when so much injustice surrounded them. Such fasting, and particularly fasting only for self-affliction, was sinful, rabbis of the Talmud said. But the Talmud also counseled “removing your hand from a meal that pleases you.”

Christianity, especially through the teachings of Pope Gregory I and Thomas Aquinas, identifies gluttony as a mortal sin. More than just excessive desire for food, gluttony involves eating irregularly (snacking), being preoccupied with eating, consuming costly (sumptuous or unhealthy) foodstuffs and being fastidious about food. And the Koran insists that improper and wasteful eating incurs God’s wrath. Eat well and live well, Islam teaches.

Of course, every civilization and religious tradition has its exceptions. Many Jewish households are celebrating lavish Passover Seders this week, and many Christian ones will have Easter feasts on Sunday. Celebrations like these are highly regulated, however. Not every day or every meal is meant to be a feast or a fast, and the one who feasts or fasts too much sins. It is far better, these traditions hold, for people to eat only the amount that satisfies them.

Among these old arguments is the novel idea of eating less than what fills one’s belly. The Talmud teaches that people should eat enough to fill a third of their stomachs, drink enough to fill another third, and leave a third empty. (A hadith in the Islamic tradition also teaches this.) Rashi, a medieval French rabbi, interpreted the Talmud to mean that the final empty third is necessary so that the body can metabolize emotions. If one ate until one’s belly was completely full, there’d be no room left to manage one’s emotions and one would burst asunder.