Fasting and fat burning
I actually agree that fasting is awesome for fat burning if used properly... but it is all for nothing without proper lifestyle to follow. I can say this from experience because i have definately several times in the past gained all of my fat back after a fast and then more. For me, healthy nutrition and exercise post-fast was absolutely essential for continued success.
I believe the warning of many (myself included) is that you can't expect to fast to lose weight and then do whatever you want afterwards. It is a trap, one that i have fallen into many times without even realizing it.
After fasting for 10 days and losing 7 pounds of fat 80 days ago, then eating nutritiously and exercising over the next 80 days to lose 20 more pounds of fat (maybe 23 with 3 pounds of added muscle), I decided this time around to use fasting as an intensified period of fat loss (in addition to all of the other amazing benefits which i look forward to) and to use the refeeding period for building muscle (as opposed to having a fat burning focus at that time). I expect to burn about 20 pounds of fat over perhaps 25 days of fasting (walking for 2 hours/day).
It is said to be highly inefficient (not completely self defeating, but highly inefficient) to build muscle in a calorie deficit... ie: muscle building works best when not trying to lose weight at the same time and actually works optimally in a highly nutritious calorie surplus of about 500 per day. For this reason, i decided to attain optimal body fat % in this fast and be able to focus on rebuilding thereafter.