It is said that how ever many days you fast, you should re-feed for half of that. So ideally, you should re-feed for about a week. I would suggest juices for a day or two, then raw fruits and veggies for a day or two. then start adding in whole grains maybe some nuts and then some meat sources like grilled fish, if you eat meats.
The re-feeding is the most important part! take it slow and listen to your body! Try not to over eat, and stay away from that junk!