Yep I absolutly loved that empty light feeling while being very clear headed and full of energy. I don't know of anythiing else that will gives the oportunity to experience that.
Everything in our bodies involves a chemical process/reaction including every single thought we have. This is an absolute >nothing< and I to mean NO_THING happens in the human body that doesn't involve some chemical process. When you've done a long fast you have changed your body chemistry completly and you literally are not who you were before you fasted. Those with mystical or religious leanings will put a spritual spin on it.
When you do a long fast you really understand why just about every religion or spritual practice advocates some sort of fasting. Some with a more practial pragmatic approach with an understanding of the chemical mechanics going on will just enjoy it more from the "observer" point of view and just enjoy the ride without seeing it through some religious/mystical filter. The empty light feeling and the mental aspects on my first 40 day Master-Cleanse was/is the coolest thing I have ever experienced.
The Master-Cleanse is about you and you only. It is about taking personal resposability for your well being. It is literally about being the best that you can be and when all is said and done that is absolutly the BEST possible thing any person can do. It is the ultimate "good" not from a selfish standpoint but from a realitic point of view seeing a much bigger picture that what you are doing for you ultimately has the biggest and most lasting impact on life and those around you.
Hang tough and secure with this understanding and when others try to talk you out of it know that they prolly mean well but unless they've experienced what you're going through there is no way to make them understand it in words. It will be useless to try and explain. Smile a lot and don't explain too much. Let your actions and the results speak for themselves.
Walk softly but carry a big jug of lemonade........;+D