not mean to bust ur balls but if u still do eat, you are prolly loosing too much water weight and is dehydrated or u took ur weight immediately after u work out...which most of the time is water wieght loss. I don't mean to show off but my work out is as follow
ran 5-7 miles 4 days a wk
spinning class in the evening 4 days a week followed by body building.
eat lean cuisine most of my meals+protein shakes.
I lost arnd 1.5-2 lbs in a wk....so this whole situation is