Yesterday I found a body building website. Although the site only recommends doing such a strict diet for a few weeks it had alot of good information on determining your Basal Energy Expenditure (BEE).
There is a formula where you can figure up how many calories your body needs to maintain your current weight with NO exercise. Mine was 1790 calories. It then goes to say, continue to eat that amount of calories and add exercise. Your eating the amount your body needs but by adding the exercise your causing your body to burn more fat. It also states you should eat 6 meals a day that equals to your total BEE calorie amount.
So I should have 1790 calories a day, divide by 6, equals 298 calories per meal. They also have sample menus and break it down even further, such as of that calories per meal, how many should be from protein, fat, etc.
Heres the link
http://www.eastcoastmuscle.com/precontestdiet.htm