Just a note if you personal trainer thinks that protein is a must for muscle growth, then they aren't very educated in what protein really is or does for you. Yes there is protein in muscles, but the amount of time that most people cleanse isn't going to hurt. As long as you still get the DRI amount of protein when you are not fasting you will be fine. For me this is about cleaning the slate so that when I am done I can eat what I'm supposed to, how I'm supposed to, and in the amount I am supposed to. Most supppliments are worthless simply because if you eat a well balanced diet you get ALL the vitamins and minerals you need from your food.
Just an educated FYI :)