How much weight would i lose in a week ?

I dont know exactly how many calories this is, but you if you are losing more than two pounds a week, it is unhealthy! I know it stinks to not be able to lose more than that a week and still be healthy, but thats how it is. If this is 500 calories less than what you normally eat, than you will lose one pound a week. Make sure you dont eat less than your RMR (resting metabolic rate---you can find out what it is using an online rmr calculator)! Good luck