Originally Posted by caloso

Using "fasted" rather than "fasting," I understood the OP to be talking about fasted rides, which are essentially getting up and going for a longish ride at moderate pace in a fasted state. I do these often, especially in the winter and early spring. Get up, drink a mug of black coffee, and ride at tempo or less for 90-120 minutes. Then eat. You are training yourself to become more efficient at using fat rather than glycogen for fuel.

That's a different thing than going for days without eating.