I will just add that when I began triathlon, I had a training partner that would routinely start our 100 mile ride days without food. One time he forgot his bottles and was too lazy to go back and get them. He did the day fasted and without much water. And those rides he and I did, well they were like races. He had a short career, but did Kona once and came off the bike almost 10 minutes ahead of Dave Scott and Scott Tinley. I called him king of the cock roaches, because when we all perished in some flash of whatever, he would survive along with cock roaches. Dude could metabolize and train on anything, usually what was cheapest or free...