When you go into a restaurant intent on eating healthy, scan the menu and find something that looks healthy, read the description and decide if it meets your criteria. Close the menu and put it down. Decision made! If you realize while reading the description that it has cheese or something you can't have find the next thing. Either way, just make a snap decision and don't peruse the rest of the menu! That's when you get in trouble. Don't give yourself that option!
I talk myself out of good choices all the time. But I am getting better at making a quick healthy choice. The longer you think about it the more likely you are to justify a bad decision. "well, I will just make sure I work out when I get home" or "I will eat really healthy tomorrow". Don't do it!