Go to a personal trainer or sports nutrionist and have them calculate your base caloric burn. This will be the absolute minimum calories you should intake each day. Once you have this number you can calculate what your workouts consist of and pretty much everything you do. You need to absolutely stay no where under 20% of your daily burn rate. Especially training your body needs the nutrients still to build and repair muscles, keep your organs healthy and keep other nutrient levels correct.
There is almost an art to properly cutting weight and cutting your food intake. 90% of people who think they are fine cutting 20lbs fast before a fight and starving themselves are doing massive damage to their body.
If you are interested I can direct you toward some stuff for you to read up on.
"A pint of sweat, saves a gallon of blood." - General George Patton