Meh, I do big rides and runs all the time with minimal fuel and/or water without adverse effect. I have even experimented with my performance, doing an XC race with water only vs fuel and I performed the same.
I started doing that stuff because I had a long bike commute when I first started riding (2+ hours) and just didn’t eat or drink anything on the commute and just kept doing it.
I listen to/read about all these people who can’t hit their intervals without fuel and I just don’t understand it. I can win a Cat1 MTB race (I race at the Pro level, but my results are closer to C1 performance) with just a snack bar before and drinking water only during and not feel bad at all. The podcast the other day was talking about how this woman was fueling poorly with a burrito during 100 mile rides, I used to do that EVERY Tuesday after work; ride 100 miles hitting up Del Taco for a bunch of cheap tacos every few hours when I felt like stopping. I would still smash the group ride I would show up to mid ride.
I did eat a shit load of cake last night before doing VO2 max, but, that just tasted good.
Unfortunately the whole thing of everyone being different means everyone is different, insisting everyone MUST EAT all the time to perform ignores the fact that not everyone needs to in order to perform.