Fasting is getting more attention these days. In a special issue of Time Magazine on "How Faith Can Heal" Jeffrey Kluger writes:

"Faith and health overlap in other ways too. Take fasting. One of the staples of both traditional wellness protocols and traditional religious rituals is the cleansing fast, which is said to purge toxins in the first case and purge sins or serve other pious ends in the second. There are secular water fasts, tea fasts and grapefruit fasts, to say nothing of the lemon, maple-syrup and cayenne pepper fast. Jews fast on Yom Kippur; Muslims observe Ramadan, Catholics [and Protestants] have Lent; Hindus give up food on 18 major holidays. Done right, these fasts may lead to a state of clarity and even euphoria. This, in turn, can give practitioners the blissful sense that whether the goal of the food restriction is health or spiritual insight, it's being achieved."

[Jeffrey Kluger, "The Biology of Belief," Time Magazine, February 23, 2009, 63]