Sometimes it is unfortunate to think that our bodies are smarter than we would like them to be but nothing is better than being in good communication with it. I too have had unhealthy eating habits in the past and have had to readjust my thinking. Fasting is a great way, and the begining, of understanding our relationship with food and other substances.
When do you plan to begin the MC? Certainly use the time to think and read. I always find it a great time to read about nutrition, spiritual healing and the like. Also make sure to pamper yourself with epson salt and lavander baths, skin brushing, walks et cetera. Use the time that you normally would cooking and eating to do something different and special for yourself.