Latest thing I have learned about myself: When on a long car trip, it's better to pick where we are going to have meals ahead of time. As in, identify a particular chain restaurant at a particular exit in a particular town, and drive there for dinner. Flexibility has its benefits, but it doesn't suit my particular brand of food insanity. (We can, of course, stop for the rest of the family to get snacks if it takes us longer to get there than we expected. And we can change the plan, but that doesn't undermine the importance of having a plan.)
If we don't have an exact plan, then as dinner time approaches I find myself obsessively scanning the horizon for blue highway signs labeled FOOD, and frantically running my mind over the possible combinations and things I could order at the various chain restaurants along the way. Should we go to a McDonald's where nothing's really great for you but I have a well-developed, reliable strategy? Or should we go to a Chili's where theoretically I could order something quite healthful but there's a chance that I could be distracted by the choices and wind up talking myself into a giant mushroom swiss burger or something? Trapped in the car with little else to do, I find I can't think of anything else. By the time I'm actually sitting down in front of a table, I've lost all my control.
But the last time we made a several-hundred-mile car trip, I made a plan to go to a specific restaurant in a specific city, which we expected to reach around dinner time. (I had coupons even!) And I discovered that I didn't obsess over the signage at all. "We're going to stop at the such-and-such at Exit n and that's that," I told myself, and instead of focusing on the blue FOOD signs I found I was focusing on the tiny green mileage signs instead, which wasn't so bad, and when we got where we were going I knew exactly what to expect and what my strategy would be, and I did fine. I chose healthful items and had a non-excessive amount, including a small dessert, and felt satisfied and guilt-free.
I think it's important to perform this sort of experiment on yourself from time to time. The results might not be applicable to others, but hey, you're only responsible for optimizing you, not them.