Why do i think about food 24 7?

I lost 100lbs in 2010. i counted every calorie and kept a daily journal. i actually enjoyed doing this. but around the holidays tapered off, eventually stopping all together. I decided to change my method to high protein low fat. i start off good everyday, but by evening i fail. i think about food constantly assessing my day and what food might be available where ever i go, or at home going over in my mind what is in the pantry, fridge and freezer. i am never hungry. what ever i'm doing through out the day thinking about food is always lurks in the background. it is very torturous. HELP!