I did the lemonade fast for 12 days and OPed twice a day. For me, it was the 4th day I finally didn't feel as hungry, and by the 7th day I wondered if I would ever feel like eating again!
I was told by the fasting group not to OP because it stimulates the liver bile. And the whole idea for a fast is to give all the organs a big rest.
Don't know if that is true, but these are people that are considered the fasting gurus at CZ.
Thought I'd throw that in there...
BTW, I haven't ever fasted again.... Maybe it is time because I'm surely needing some help here. Been off the wagon for about 9 months due to my Mom's illness.