In college I once went 6 days fasting. (to be fair, I had a glass of apple juice each morning to placate my girlfriend who thought I'd die).
It had occured to me that I had never been hungry in my life. Maybe a bit peckish, but never really hungry.
After a few days, the gnawing hunger transformed into a kind of quiet listlessness.
I was aiming for a week, but only made it 6 1/2 days because there was a fire drill and I was night security, and no way was I marching around the dorms all night with a flashlight without some caffiene and sugar.
It wasn't a spiritual thing, and i didn't have any kind of fasting-manifesto worked out, but it changed my worldview a bit.
If I skip breakfast, I no longer say, "man I'm hungry" when lunch rolls around four hours later.
(I think I lost a few pounds, but a Nurse firend told me that when fasting, the body shuts down non-essential stuff, so you burn less calories)