How many acres of ag land does it take on average to support one person in the US with food for a year?
To put it another way, for each acre of ag land given up to a city, how many fewer people can be fed. I realize it depends heavily on what and how much a person eats, ie. a small vegan would require way less than a large meat eater. But there is an average or a range. I'm thinking along the lines of simple numbers like so many bushels of corn per acre and how many bushels each day to feed a person for a year.
Ignoring imports and exports creates a huge error given our exports. The error for eating animals is likely to be smaller. If one knows the efficiency of conversion of corn to cow for example that helps. I would guess that is about 25% but I have no data to back me up.