But like, there's variation in how much food people will end up eating, and at least some of that is not variation that you can predict in advance. So unless you have enough food that you routinely end up with more than can be eaten, you are going to end up with a lot of cranky people a non-trivial fraction of the time. You're not trying to peg production to the mean consumption, but (e.g.) to the 99th percentile of consumption.
You seem to think that people that are not completely satiated are automatically cranky. That doesn't match my observation.
Also you may have multiple dishes. For example we mostly start with a collaboratively prepared soup - which thereby will be the right size by construction. Later we have some snacks or sweets or fruits. First the fresh ones, later if needed packaged ones.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.