...Andrew Greeley is often irritating in his pronouncements, his blog-like book Everything You Wanted to Know About the Catholic Church But Were Too Pious To Ask is entertaining and surprisingly traditional, given the author. Written in 1970, I think he was trying to buck the Zeitgeist just as now he tries to buck the "conservative" Zeitgeist. (You can see his contrariness in the form of asking, in '99, whether voting for Bush was a mortal sin - he's traditional enough to mention mortal sin but liberal enough to ask the question concerning voting for a GOP candidate.)
Anyway, he writes with regard to fasting:
We used to do it grimly, protestingly, unhappily, and badly during Lent. We don't do it much any more. The idea was that we fasted to expiate our sins. A lot of people today do not believe in either sin or expiation, but they still fast, often throughout the year, for reasons of physical health or attractiveness. We have, in other words, more dieting and less fasting, which may be a paradox but which is probably a contradiction. Might not Lent and Advent be appropriate times for dieting, times when one takes care of both one's spiritual nad physical health by demonstrating resourcefulness, self-discipline, and self-control? Could it be that we have blown a very useful idea on this one?