Wow, that's great!
Getting away from the "supersize me" diet is a great step toward health.
To make the transition easier, it may help to try to add some fruit, vegetables and juices to the diet before you start.
For sure your body is going to find some stuff to clean out.
After the fast it should be easier to keep your distance with the "fast food nation", as the addictive chemicals added to fast food will be being removed by the body during the fast.
Without those substances in the body, the cravings for that food should be less.
Good Luck!