Re: 21 day fast maybe 30 days

That 2 day count is right and I'd guess in 2 days you will revert to fat unless you're very very very insulin resistant. I'd guess insulin drops in 1/2 every day. You start @ 10, you'd be 5 after 24, 2.5 after 48 and 1.25 by 72 hrs and @ 1.2 you're definitely killing the fat and not muscle. However in those 72 hrs you'd burn other tissue including bone and organ tissue as well as muscle.
That part of your math is right.
The twist is this, its 9 calories per gm of fat and barely 4 for muscle or other tissue. So 2000 calorie deficit and high insulin = 500 gm+ muscle, over a lb. In 3 days its 3 lb and maybe not just muscle, it may be something a lot more important.
In any case your body pretty well fights that and gets you to be lethargic and "dead on your feet" and cold and miserable. So you will not lose 3lb muscle in 3 days. But, you will lose 1000 calories out of your metabolic rate. Your 2000 calorie BMR drops to 1000. The problem is, it stays @ 1000 through the fast.
That is almost what happened to me. Now I understand that, I will be breaking fasts with veggie and carby food a few days, jus tto enjoy it and get it outta my system, then fat up a few days eating 3000+ nearly all as fat and the end of my feast will be more and more fat and higher and higher calorie and then abruptly fast. Ramp up via veggies and low calories, and slowly move to higher and higher with fat and then abruptly drop to 0.
Like 1200, 1300, 1400, 1500 .... 3000 (all as fat) and 0.
There is a proper way to fast LOL.
Thanks.
Srinath. Tweet