Can’t really speak to “tech” stuff too much but will share just a bit from my primitive world.
I’m a musician, piano / keyboard player to be more specific. And sometimes gigs can go as long as 4 hours+ of solid play, not usually, but sometimes. I’m not typically in large groups, sometimes solo, sometimes with up to 3 other people, but usually not able to sit back and relax when I play like I might if in say a 10 or 15 piece band. I’m typically front and center for a large block of whatever time is called for.
That can be both physically and mentally challenging getting through something like that. When I first started out, I would have to be careful about hydration because the last thing I need to have happen is to start cramping while playing. That happened one time and people were worried that I was having a heart attack. No, I just needed water. Had to ask 3 or 4 times to get it but finally did, and the show resumed. I since will NOT do a performance without my trusty drink bag with me.
But there was more. I would start getting tired and a bit “foggy” as I played. An hour in, two hours in, it seemed to get harder and harder. I tried adding some soft drinks. Helped for 5 to 10 minutes, then it was worse. Tried adding some soft drinks with caffeine. Jacked up my nerves more than just the sugar but still the “crash” 10 minutes later. Just never seemed to get it figured out… until…
I finally decided to change the approach. Before a stage performance, I would have a heavy meat based meal, if not carnivore, keto. My favorite was somewhere between 1/2 pound and 1 pound of ground beef (usually hamburgers), and a couple of sunny side up eggs on top. Maybe some cheddar cheese if I felt like it. No veg, no bun. Not much for condiments. Water or coffee.
Outcome? I could go 3 or 4 or 5 hours and feel GREAT! And so long as I was careful about anything I ate or drank, I was just fine. Playing for events where there was food involved helped me to realize that even a single cookie or a few sips of punch was likely to have me plunging right back off that ledge I had tried so hard to avoid and end up tired and wondering if I could make it through. It is sometimes hard for people to understand but that’s my reality.
About the only thing I will take on stage with me other than just water is either seltzer water or club soda, I have no issue with either of those. (I’ve not tried coffee though I have sometimes had that with my hamburgers before the show without issue. I’m not one that drinks coffee all through the day though anyway, I’m a morning coffee person and then I’m done.)
Would that apply if I were in the tech world? I suspect it would. If I wanted to be on top of my game and sharp I’d be wanting to very much avoid the sugar and carbs and make sure I was well fed with good fats and protein. It works for music, I think it would work for other things, too.
Maybe TMI. Just sharing.