Argh I do exactly the same, I found myself doing it earlier despite having had the most disgusting bingey weekend ever and putting all the junk food on the side with "eat me" written on it for my housemates...I was just standing there stuffing crisps.
Find something you can completely immerse yourself in doing - yesterday, I agreed with a friend that I'd do some work and then check in on each oter in an our to see how much we'd done - three hours later I'd been working solidly without thinking.
I'd adise you to just sit down and think why you pick - and write it down. I've got a poster up on my wall now saying "why am I eating this" =- and I narrowed it down to 6 reasons - anxiety, sadnes, loneliness, self hate, guilt and boredom (thanks to a website on comfort eating I found!) - after each heading I've put a reason why I souldn't be feeling that way, or how I can sort it out. For example, under "self hate" I've put "Don't be silly, people like you - it's just paranoia". Under "guilt" I've written "Eating will only make you feel more guilty, and will make you put on weight which will turn into self hate and more guilt"
So yes. Something to stick on your wall where you'll see it is good - it sort of stops you in your tracks. I'm thinking of sticking something in my fridge and cupboards too....
We can do it!! now take your mind off it 
