Based on my own experiences, I'd actually expect performance to improve since the body isn't using resources for digestion. I'm not a weight lifter, but I know bicycling is significantly harder shortly after eating and my other current sport, freediving, is much, much easier after fasting (my static hold time is close to 2 minutes longer when I haven't eaten in the past ~12 hours).

One interesting observation I've had from freediving is that some of the signals we get from our bodies are far less urgent than we tend to experience them. The main one, in that sport, is the urge to breathe and it's actually not an indication that the body needs oxygen. It is, instead, an indication that CO2 is building up and you can expell it by breathing. Freedivers learn to experience that sensation and push past it.

I'd imagine hunger is very similar. People accustomed to eating whenever they're hungry will panic an experience "low blood sugar" when they don't immediately respond. But we know that humans can go weeks without eating before we die. Pushing past our accustomed non-resistence to hunger will likely be uncomfortable, at first, and then become normal with practice.

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Exactly. People are way too used to eating all the time.

This is exactly what I've noticed as well. Even a few hours after eating my runs feel sluggish. All my PRs are from running first thing in the morning, before any food.

Early on when I was still experimenting with the diet, I did drop down to around 160-165lbs, and my running performance took a drastic hit. I remember struggling to complete a three mile run one day, when 6-10 was typical for me at the time. I felt normal up until around one and a half miles in, then I hit a wall, which made me turn back early. It was a really odd sensation, the will was there, but I was weak, almost like I had run out of gas. I'd tell my legs to move, and they'd barely follow through. This wasn't soreness, or fatigue, but weakness, subjectively a very peculiar sensation, and not at all subtle.

Being weak like that did freak me out a little bit. I simply added more calories (ate more), while maintaining meal timing, and my distance was back to normal in a week or two though (actually slightly better than my pre-diet "normal"). This brought my weight up to a steady 170-175lbs, which I've been at for about two years.

It's really important with this style of diet to get adequate nutrition. If you're eating less, or timing your meals, you really need to maintain a high-quality diet. You're likely eating less than most other people (or what you're used to), so the nutrients and calories you do take in are that much more important. Eat a lot of fresh vegetables, moderate carbs, and high-quality protein. Extra fiber is also really important, because the extra volume helps create a sensation of fullness, making the diet easier to stick to. You'll also want to drink extra plain water, to accompany the fiber, so your body chemistry doesn't get out of whack. Don't eat any refined sugar at all, it's a powerful appetite stimulant, and will make the meal timing much much harder to stick to.

Edit: I mean, I read an article once that said ketones could enhance performance in weight lifting.. my exercise is Cross Fit training at a Crossfit gym.

And in my experience even just doing an hour of exercise in a fasted state can dramatically impair my immune system as well as higher brain function.