Today I did 80 miles morning ride with almost 6,000' of climbing on an empty stomach (no breakfast) and did not bring any food nor money!
I brought four 550 mL bottles with salted water. The salted water would have been enough except, riding with zero calories force me to drink more often even though it was cold up in the mountains the first 3 hrs (<75F) of the ride. And I love the taste of salted water. To me, it tasted like milk and perhaps, feeling the hunger mid ride, forced me to drink more than necessary and also because I'm peeing nearly twice an hour!
I was doing great until I ran out of water at 57 miles with 4,500' climbing already accomplished and 1,500' remaining.. I started losing power after that and my entire body is starting to feel weak, including my heart. I struggled the rest of the way home and there's a strong headwind to make things even harder. Fortunately, my legs did not bonk, nor cramped during the ride. I did experience cramping but only 4 hours after I got home and sufficiently refueled, rehydrated, and rested.
I won't be doing this kind of ride again. Peeing so often and not able to replenish your water bottles proved to be a horrendous problem. I didn't feel the hunger at all. I think the salted water kept me feeling satiated quite well. But the situation have magnified my sense of smell for food and I can smell food from miles away and the smells made me feel hungry! If only I could replenish my bottles for free, I could have only brought 1 bottle of water and powdered salt.
On a positive note, I did my personal best on the 4,500' which is surprising given the no-fuel situation and I tried to do the climb at reduced perceived effort to account for no-fuel ride. I've done this climb many times so I know how to pace it based on perceive effort. So achieving PB here given the uniquely unfavorable situation is most surprising.
I've done unfueled, empty stomach rides before but only to up to 50 miles so this is the longest so far. I'll probably limit these un-fueled rides at 50 miles and in city loops only few miles away from home so if anything feels wrong I can head back home quickly. Fueled rides doesn't seem to make me stronger and riding unfueled is major time and money saver also if you'll be drinking only salted water.