3. It isn't just fast food that serves over-large portions.
I have wished for years - and often suggested to restaurants - that they offer a 'half size' portion. Sure, it's nice to have an entire meal left over to take home, but that only works if I'm in a position to take it home. Some of the restaurants are starting to offer smaller portions of their meals, but usually only during lunch; a very few are offering them at all meals.
We don't need regulation - you can't legislate behavior in any meaningful way. If we made a move to using smaller plates, though, it would be a good start. Plates in restaurants are the size that serving platters used to be . . .