I dont remember which talk show i saw this on but anyways here's the concept. Mostly works with religious people. The concept is to focus on God when you get a craving, like fighting gluttony. So eat when you need to, but when you start to salivate when you see someone eating chips, or a candy bar at a store or a midnight snack of ice cream. Focus on God, pray to God (or meditate how ever your religion sets it). It's kinda like the concept of Lent, except it's not giving up one item, but the whole sin of gluttony.
you mean moderation? calling it a prayer is kind of extreme, then again i do have my own belief that there's no god. but hey, if it works, more power to you.
i think this is indeed very similar to some sort of pyschological therapy aiding diet.... try to convince the 'receiver' that they don't actually have the desire to eat...