Dear Maria...I just got on the scale and I've gained 18 lbs. How could I gain so much and not realize I was doing it?
Oh, this does happen. You are certainly not the only one.
This can happen while you aren't paying attention. It happens when you eat mindlessly and forget to notice what you're doing. This is a perfect example of how your actions get to be so automatic, you completely lose touch with them and they run on their own.
A thought: Slow yourself down, give yourself time to notice.
Think before you act. Think before you act.