When I was younger and trying to give up hard drugs, one thing I did was to clip the money in my wallet together with a red paperclip, which I chose as a symbol of how drugs were bleeding me to death both physically and emotionally. Every time I thought of buying a hit of acid or speed I knew I would have to reach into my wallet and see that red paperclip. Soon just carrying my wallet around served to remind me of that thing. At first I fumed at the times I stopped myself, thinking that I had missed out on another "good time". But soon things started shifting the other way and I didn't want to lose momentum. And as my head cleared (literally!) I began to realize how much drugs had harmed me, and the red paperclip reminded me of that as well. I still have that paperclip, and I have been clean off hard drugs for 30 years this year.
Overeating is a different problem, of course, but perhaps something symbolic would help you too. I just can't think of what might help.
Nobody living can ever stop me
As I go walking my freedom highway.
Nobody living can make me turn back:
This land was made for you and me. (Woody Guthrie)