If you find yourself jumping back and forth between eating Cleanly and falling off path and eating Uncleanly - I'd challenge you to ask yourself a question:: Why? Why do you want to eat Clean? Physically make a list. Write down your reasons, and examine them.
I thought about this question - Why - for the last few nights, and my list is short but direct. These are in no particular order of importance. They are all equally important to me.
1. My outsides weren't matching my insides. I felt trapped in a body not my own - overweight, and ungainly. I felt young and vital inside. I looked older than my years on the outside.
2. I have a long family history of heart disease in my family. My parents died young. I have a husband and son who love and depend on me. I didn't want to leave them too early; I didn't want my selfishness and inability to control myself to take me away from them prematurely.
3. I have a lot of really nice clothes I simply couldn't wear anymore. I had outgrown them.
4. I didn't feel well. I was easily winded, unable to keep up with my family, and had zero energy. I snored - loudly. I was irritable and cranky. I found myself easily discouraged and depressed. I wasn't healthy.
What are your reasons to stay on track? Why? Why are you Clean? When you examine the ( probably multiple ) reasons for you to eat Clean - you'll agree, you have a lot of good motivation to stay on track. I know I do. The list above is strong motivation for me. Self examination is tough - probably one of the toughest things a human can do. However, when you remove the excuses of low will power or lack of preparation...you'll find that list of reason you prepared. Put that list somewhere you will see it daily - on the fridge, next to your computer. Refer to it as needed. Think about it as you say your focused imagery phrase.
These things will help keep you on track, and keep tempting Unclean foods at bay.