when you fast:
Insulin drops and glucagon increases
Fat oxidation increases (fuel)
Increase GH
Along with a lot of beneficial things. After 24 hours it all slows down though, and your body tries to go back to homeostasis, so there is no real need to fast for more than 24 hours. Im in the middle of a fast right now TBH my last meal was at noon, so ive just been drinking water and some xtend all day till noon tomorrow.
Recover pro is something I will look into