I was 1st day yesterday and did not do the P&B shake. Didn't even really understand what it was until I read about it this morning. I just don't want to interrupt the Master-Cleanse process by putting something on top or in the middle of it. If I'm going to do this, I want to get the best results possible, so I don't want to take any chances of "clogging up the system". (no pun intended ... well, yes there was!)