"I'll say that if you undertake this, you will learn a lot about yourself and about how habit-driven most of our eating is. And, how darned much time we spend thinking about eating, preparing to eat, eating and cleaning up after eating."
I totally agree with this. I am a pretty introspective person in general, but fasting really brought food and eating habits into focus.
As far as exercising. I do tend to slow down a bit. As you might have guessed by my screen name, I am pretty active especially with outdoor sports. So fasting a hard training for a half marathon are not really compatable for me. But I usually continue with the running, and have never turned down an opportunity to hike, ski, bike... whatever, with friends just because I am on a fast.
I have found it a little difficult to go about my normal workday ruitine, however. Just too many cues and triggers to surrounding food. For example, for most working folks lunch time is an important part of the day. It can be, almost, a ritual. So I usually do my fasts when I am out of my normal ruitine, vacation, long weekends, or when I am working at home for a while, etc. I am very fortunate that my work allows me such flexibilty.
Sometimes I treat the fast like a week at the spa (not that I have ever had the chance to go to an actually spa). Lots of moderate exercise, reading, thinking, and writing. (I am a research scientist so "publish or perish" is a reality.) Again, my work enables we to do this and I know not everyone can, but most folks can find a little time and work around their normal schedule to work in periodic fasts.
I am really glad this thread was started. I have thought about beginning one for a while now, but as mecompco noted, there is so much controversy associated with fasting I didn't want to stir the pot too much.