In setting forth the rules of Yom Kippur, the Torah says nothing about refraining from food or drink, only commanding: “You shall afflict yourselves.” Examining talmudic passages in which the rabbis determine that the phrase in fact refers to fasting, Julian Sinclair finds clear hints at the purposes of the practice:
[After arguing over the exact way “to afflict” is to be interpreted as meaning “to fast”], Rabbi Ami and Rabbi Assi share a series of reflections about what happens when desire and fantasy slip out of control and restraints break down: you start to view anyone else’s property as legitimately yours, says Rabbi Ami; you see all the forbidden sexual relationships as fair game, claims Rabbi Assi.
This series of observations ends with a pair of comments about the snake in the Garden of Eden who is cursed that “its bread shall be the dust.” Rabbi Ami interprets: “even if it eats all the delicacies of the world, they taste [to the snake] like dust;” Rabbi Assi says, “even if it eats all the delicacies in the world, it isn’t satisfied until it eats dust.” . . .
I suggest that the rabbis interpret the snake, emblem of untamed desire in Genesis, as an image of addiction. One who surrenders to an insatiable lust for the food, drink, or substance that he craves is fated to a jaded state of sensuous degradation where everything tastes of that one thing or where only that one thing satisfies. . . .
On Yom Kippur, the Talmud is teaching, we withdraw from engagement in the world of eating, drinking, and bodily pleasure. This offers a chance to release ourselves from the thoughts, fantasies, and desires that can so preoccupy us, and rebalance our relationship to eating.
Read more on Times of Israel: http://blogs.timesofisrael.com/why-fast/