Sounds to me like you KNOW you need to change and in fact know WHAT to change. So maybe you need a check in buddy or something. Someone you have to be accountable to EVERY day. Sometimes knowing that you will have to 'fess up face to face that you ate crud and feel like crap is enough to keep people from doing it in the first place. And maybe ask people around you to not offer or leave stuff you don't want to be eating (like the candy).