Would it not be possible to introduce pre-flight meal orders (for instance at OLCI)? If you didn't you would be left with whatever there was on offer otherwise. I'm also sure menus are prepared months in advance so no surprises there...

Pos:

1. It would reduce food waste,
2. You would be served what you would want to eat.

Neg:

1. You might change your mind on the actual day
2. The menu might have changed slightly due to unforeseen circumstances.

At least you would be guaranteed a meal you could/want to eat.

Of course this could add costs to the process of getting the correct food to the correct flights BUT they seem to handle this with special meals (again, only a fraction of the total meals that goes out)...