The Science of Fasting

Hmmmm, some (bad pun) good food for thought...
I am admittedly a novice but have tried to read everything that has been posted here and just other general research. My wife and friends think I am crazy and can't fathom fasting.
I've done 80-90 hours a few times and I am again in that range currently.
I feel really good and think I could keep going for several more days, I was a little tired after shoveling/clearing 5-6" of overnight snow this morning. The pangs are quite minimal and my energy is still very strong. I am noticing that I get cold/chilly much easier, that's about it.