Intermittent fasting does have its limits.
I found that after about eight weeks of IF where I would have a narrow feeding window I started to develop some kind of metablic disorder (possibly adrenal fatigue) and couldn't seem to get enough sleep or have any energy during the day. Nowadays I can function pretty well on about seven hours a night. Here's a pretty good timeline of how fasting seemed to work on me.
week 1 : hungry all the time, odd mood swings
weeks 2 -6 : very high levels of energy, function well on fairly little sleep (like six hours a night)
weeks 7-8 : feeling pretty normal, hunger is an afterthought. Sleeping like ten hours a night.
weeks 8-10 : deader than hell, can't get enough sleep, not hungry at all
The way I see it there are two useful options for fasting (depending on how you respond to it) that I did not pursue. One is the cheat day every three days or so, where eating windows don't matter. The other is fasting just one solid day per week. That way your metabolism is not going to suffer from many weeks or months of a consistent (and small) feeding window. It will be more miserable to go this route, because you'll always be stuck in my week 1 phase of being hungry while fasting, but I think it is more sustainable for weight loss. Be nice to your adrenals and don't respond to low energy with more fasting.
I found that after about eight weeks of IF where I would have a narrow feeding window I started to develop some kind of metablic disorder (possibly adrenal fatigue) and couldn't seem to get enough sleep or have any energy during the day. Nowadays I can function pretty well on about seven hours a night. Here's a pretty good timeline of how fasting seemed to work on me.
week 1 : hungry all the time, odd mood swings
weeks 2 -6 : very high levels of energy, function well on fairly little sleep (like six hours a night)
weeks 7-8 : feeling pretty normal, hunger is an afterthought. Sleeping like ten hours a night.
weeks 8-10 : deader than hell, can't get enough sleep, not hungry at all
The way I see it there are two useful options for fasting (depending on how you respond to it) that I did not pursue. One is the cheat day every three days or so, where eating windows don't matter. The other is fasting just one solid day per week. That way your metabolism is not going to suffer from many weeks or months of a consistent (and small) feeding window. It will be more miserable to go this route, because you'll always be stuck in my week 1 phase of being hungry while fasting, but I think it is more sustainable for weight loss. Be nice to your adrenals and don't respond to low energy with more fasting.