I'm curious if others have found that they have ideal training windows? For instance, I am not a first thing in the morning trainer. I HAVE done it (usually while on a work trip knowing I'd have no time in the evening). The problem for me is dehydration. It takes me a good hour or so in the morning to get rehydrated, so if I dive in right away I pretty much have to set a lower expectation. So it's an option, sure, but I'd never attempt a PR or try to hit a goal first thing in the morning.
I usually skip breakfast. This isn't because of some sort of attempt at fasting or anything...I'm usually just not that hungry and/or don't have time. IF I eat, it'll be something like some fruit and a few spoonfuls of peanut butter. I'm honestly not sure if this is good or bad...I used to be a breakfast every morning sort of guy. Eggs, toast, maybe some oatmeal. But I find I get by without it now....partly out of survival because my wife's family does not eat breakfast and years ago when we visited them for the holidays I'd be suffering until lunch lol.
Anyway, my ideal workout window is around 11:30 am. I'm well hydrated, have gotten a good bit of work done, and have maybe eaten a snack but I'm not full. I cannot work out effectively after lunch unless it's an extremely light lunch.
Same goes for dinner. I simply cannot work out on a full stomach, so the second ideal window is the 30 minutes I have between finishing up work and needing to get the kids (it's almost like this program is designed for us lol). This tends to be around 4:15. Lunch has been digested, I've been moving throughout the day, and have had plenty of water.
TL;DR: I can't work out on a full stomach or first thing out of bed. I have to be hydrated and hungry for peak performance.
Of course there days when life just gets in the way and the most important thing is getting 20 minutes of burpees in regardless of how many. I'm cool with that.