Restaurant portions, at least in the U.S., are ridiculously large so I’ve gotten into the habit of asking the waiter to bring a to-go container WITH THE MEAL. I then immediately put at least half of the food away in the container and set it aside. (If the food is there on my plate in plain sight I will likely pick at it, but once it’s in the box, it’s off limits.) This tip allows me to 1) enjoy the rest of my meal, and my dining companion, without the distraction of, “I really should stop . . . well, maybe one more bite . . . Stop it! . . . OK, this is the last bite for sure . . . ” and 2) I can enjoy a tasty “doggie bag”  lunch or dinner the next day, provided it’s not a fast day.

I suppose you wouldn’t have to involve the waiter at all. You could just discreetly bring a container from home, casually transfer half the meal to your own container and set it out of sight. It might even be fun to see the waiter’s shocked expression when he thinks, “What?! How did she eat HALF the meal ALREADY!?” 🙂