Could someone please comment on this.. I have the exact same question!

I've done it without the apple juice and it worked just fine.

I've also done the flush with as much apple juice as I could drink 24 hours before the flush. That also worked out fine.

experiment with your own body, some people need more help than others. I have done it before with no juice at all and had good results. Most of the time I do use it, but I do not think there are hard and fast rules. More like guidelines and find out what works best for you. :)