Note that in ramadaan they also don't drink any water during the day; and many who can afford to, flip their schedule to sleep through the day so they can eat at night.

Also, according to superfreakonomics, this wreaks havoc on gestating babies. Seems like all harm and no benefit fasting (which, perhaps is the idea - Jewish fasting on Yom Kippur is specifically spoused to be a soul-torture/soul-searching experience - both translations are valid - although it is often not experienced as either)