From my experience it is a lot easier to "fast" or do a master cleanse after a liver flush. It helps with the transition and I feel it is more beneficial. PLUS EASIER....and life being a little easier is defintily helpful.
Yes, it is ok to fast on the day of the flush. But . . . be sure you get well hydrated! Being well hydrated when you start the flush can mean the difference in felling great as you finish the flush or feeling like you have been run over by a Mac truck.