The fast will help some, but what I learned (the hard way) is that the REAL discipline is only learned while you are eating. As I've come to say repeatedly, "It's easier to fast than it is to eat right."
How long do you plan to stay on the MC? I personally believe that more is accomplished during a lengthy fast (especially in terms of food addictions and cleansing). So, by all means, do the fast for the cleansing benefits and to break addictions, but understand that how you eat afterwards is going to be the real work. Do your research well while fasting, make a plan you KNOW you will stick with, and then get ready for the rubber to meet the road. Fasting is EASY, it's eating right that's tough. And we can do it! God bless and fast on!!