I recommend review Dr Doug Lisle’s talks:
Willpower
https://m.youtube.com/watch?v=ciZ4zN60Lq4How To Lose Weight Without Losing Your Mind (Full Lecture)
http://www.youtube.com/watch?v=xAdqLB6bTuQThe Pleasure Trap (Full Lecture)
http://www.youtube.com/watch?v=nxf4kj8Rb6YNo need to be perfect. Just be good. Get thinking in order. Understand deeply. Practice. Some people do seem to have addictive personality (like Chef AJ or Andrew SpuFit Taylor), and benefit from approaches that extinguish the addiction. Others can take moderate approach. Only you know which you are.
If you are sometimes unprepared, then work on prep, and make backup foods. For example I like to have some extra staples like potatoes, brown rice, lentils, bean, etc. always in the refrigerator. For travel I often take a tupperware container of baked french fry snacks.
If you sometimes need an indulgence, then work on on plan indulgences: air popped popcorn, whole grain crackers, fresh fruit, black bean brownies, sweet potato-pumpkin pie, banana ice cream, etc.
Skip the soda and try sparling water, lemon water, juicy fruits (watermellon, mellon, oranges, grapefruit, grapes), etc.
If you are here you are on the right track.