I, too, have to be alert when I'm at the grocery store. I keep a list in front of me, which keeps getting shorter and shorter. I still have poor impulse control. I end up having to return items back to their shelf. Whenever I buy something, even if it's on my list, I ask myself if it's within my calorie range or if there's a healthier food I can replace it with.
It's wonderful to have you join 3FC.