Your
body cannot physically lose a
pound a day. At least not unless you are in some sort of actual
starvation scenario, and then you will lose muscle. You are working out too much for the amount of food you are taking in. You should never burn (with exercise) more
calories than you are taking in. Your
body needs
energy (calories) to do things like breathe, make your
heart beat, digest the food you are eating, repair cells, etc. As losing_it pointed out, most places say you shouldn't go below 1200
calories. You may lose weight on you current path, but it will be muscle.