I should have been more definite in my prediction - only fast 800 would do a stone in 21 days. Meh, I dunno, if they all do it properly they’ll drop that easy enough - it certainly won’t kill them. No magic outside of extreme calorie deficit, I’m confident in that. Easier (possibly) to stick to due to higher protein/low carb food. Been there, bought the book, lost the stone, lost the will