It's not that simple, that's all I can say. If you don't provide enough energy over a longer period of time, you'll lose weight - but over all this topic isn't as simple people think. I'd suggest not to worry too much, jsut work out hard, eat as much as you need, period. If you want to really get into this, you might have to do some research, pick up a book, a couple of questions on a msg board won't provide all the information you need. It's not only when you eat, it's what you eat too, etc etc.... but like I said, if you don't lift like everyday, if you just try to be in good shape, don't worry too much, just work out, that is after all, what it's all about.