I have tried fasting and eating and both produced the same results. I do recommend the apple juice or malic acid for a week prior though as they do help soften the stones for departure. I would say eat up to the day of the flush in a light and healthy way so that you have the strength to endure the process. Otherwise you could end up feeling very weak and depleated afterwards from the Epsom Salts . Also keep WELL hyrdated before and after the flush and possible invest in some calmag fizz by Baywood (A perfect calcium/magnesium combo) and some Emergenc electrolyte drink packets that rebalance your vitamin C and mineral reserves. If you have a juicer carrot juice is amazing as a post flush regenrator for the liver. As is olive oil 3 times a day 1 tbs at a time with 1 tbs of lecithin granuals mixed with it or seperate. The lecithin has made HUGE difference for me in healing my liver congestion. I wish I had done it sooner. Just be sure to back off of it (do it 1 time daily but keep doing the olive oil 3 times a day) as soon as you start feeling like your liver is functioning better so you dont over do it.
I also eat Bieler broth after my flushes as it regenrates the liver salts quickly and gets rid of the enflammed feeling faster. You can find the recipe at http://www.askshelley.com Just look in the FAQ under The Essential Recipes. Any recipe you find there will be very healing to this process. I especially like the protien shakes as they help rebuild strength also.