how do you know how many calories to eat in order to lose weight?

I completely understand where your coming from and often find that no matter what I do I just can't seem to lose that extra bit of weight...especially now christmas is over and i've just added to the weight I already had. If you can't exercise the best thing in my opinion to do is suppliment any fatty foods for healthy foods. An average calorific intake for a woman is 2000 calories a day so in order to lose weight perhaps you could limit this slightly and instead aim for 1500 calories. Doing this and with gentle exercise in time you may begin to notice a difference. Just recently my mum has dropped a couple of dress sizes because she has recently found out she is illergic to sugar so she has now cut it from her diet. Because of this small change the results have been enormous in terms of the weight she's lost...it really has spurred me on to do something.