What I learned from this:
1. Meal timing is not as important as you'd think, but it's still important. This diet involved a new trend called Intermittent Fasting. The idea is that you fast for 16 hours with nothing but water, then do your workout, and then feast for the remaining 8 hours. It increases insulin sensitivity, reduces ghrelin (hunger hormone), and increases "growth hormone." As long as I kept myself preoccupied, it was no big deal. If my stomach started to hurt or growl, I'd just have a few sips of water and I'd be fine. Some days I was so busy that the first chance I had to eat was 8pm, and I needed to go to bed by 10. Those days were hard to cram 2600 calories down my throat, but I learned which foods were great for those situations (nuts, peanut butter, and beef jerky are at the top of the list). I was allowed epic cheat days, with the stipulation that they were followed by a 40 hr fast. Again, not as big of a deal as it sounds, if you can keep your mind off of it (and if you can keep from getting cranky in hours 24-40).
I won't share the inappropriate details of how I learned this, but I learned that your body doesn't necessarily consume all the calories you feed it. Eat fast enough, and you won't keep all those calories. However, I don't suggest ANYONE use this as an excuse to eat more than what they ought to eat. I had no way of measuring how much exactly wasn't digested. It could be a lot less than you think.
2. Don't let bro-scientists and the current diet fads fool you: not all carbs are the same, and not all fats are the same. If you work with a trainer, they'll probably tell you your diet needs to have x carbs, x fat, and x protein to meet your goals, and that it doesn't matter how you get those nutrients. 6 weeks after starting my program, I was diagnosed with astronomically high cholesterol. My low carb/high fat diet certainly wasn't helping. I had been eating ridiculous amounts of eggs, red meats, and dairy over the previous month and a half. I replaced many of those fats with nuts, avocado, and fatty fish. But mostly nuts. They're like candy to me now. The low carb part of the diet naturally got rid of white flour and refined sugar. It's much more rewarding to get your sugars from fruit anyways. I'm a fan of clean eating now: if it comes in a box, eat sparingly.