Thank you for inviting my further contribution. My initial interest in intermittent fasting was sparked by reading about autophagy induced by fasting. There are all sorts of varying posts regarding what it takes to induce autophagy by fasting but the one I'm using posits that after 18 hours of fasting your body will begin to consume damaged and dead cells as fuel and subsequently replace them with new cells. For someone who has lost about 85% of my kidney function, that process holds great appeal. As for sleeping, I don't have that problem, although at 74 years old I do have an enlarged prostate that does cause me to wake up every 2 hours to urinate through the night. Fortunately, I usually don't have any problem falling back to sleep after 10 or 15 minutes. I fence competitively at the national level so I get plenty of exercise and also like HIIT. I use the stairs in my apartment building. I climb 50 flights up and down taking 2 stairs at a time just about everyday. I also have been practicing tai chi for the past 40+ years and do that for about half an hour everyday. Also practicing Zen meditation for the past 40+ years.