I don't know where the ultramarathoners are online.
A friend of mine is an ultramarathoner and used to compete in the Western States 100 Endurance Run, so a bunch of us used to crew for her in the race. Think about doing 100 miles of trail, with 18,000 feet of elevation gain, and finishing that in 15-24 hours.
I would make a point of being at a checkpoint when the elite front runners came along. Once they were checked in by a race official, they would briefly sit down while their crew would change their shoes, stuff cookies into their mouth, change water bottles, check on GU levels, test or replace flashlight batteries, and then push them out onto the course again. Yes, it was like a pit crew at Indy. I paid particular attention to the runners who were doing the best and what they were consuming, the 50% flat Coke and 50% cool water with a pinch of salt, and so forth. That was quite popular on a hot day. On a cool day, it was more of the thicker powdery carbohydrate and protein mixes in tepid water. If it got cooler yet, everybody was into bananas and then more cookies dipped in peanut butter. The whole secret to being a successful ultra runner is the ability to ingest food and water and being able to digest it while you are continuously on the run.
I would think that if you were trying to do something extreme, like covering the whole JMT in a few days, you have to do extreme things like I mentioned. Most of us, I suspect, aren't doing anything that extreme, and we are moving along through boring trails until we get to some scenery, and then we pause for a photo and lunch.
Come to think of it, I could use a cookie with peanut butter right now.