Pick a goal related to skill in addition to your weight goal. Aim to lift a weight you've never been able to lift. Work towards running a distance that right now seems impossible. You'll amaze yourself with what you can do.
I didn't lose a lot over training (actually I gained quite a bit because I had a baby), but if you told me not that long ago I'd complete a half-marathon and I'd want to run a full the following year, I'd have looked at you really funny. No number on a scale can ever take that from me.