[dragonwriter]

That's a factor, but even if you just lose fat, you calorie expenditure from the same activity pattern, ceteris paribus, will be reduced (because you are carrying less weight), so if you return to the eating pattern which at which you were stable at the higher weight (assuming no other systemic/metabolic changes, just the fat loss) you will gain weight asymptotically approaching the the weight at which that "normal" calorie intake had you stable before.