This matches my personal experience. I found the gains acquired while IFing - exercise at around 8pm after work and fasting afterwards until noon the next day - to be very consistent and lean.
Same I do time boxed intermittent fasting, usually exercise in the morning, and eat a single large meal between 2-7PM. I primarily do cardio (distance running), and didn't notice any performance hit.
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.
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.