… or, Why exotic modern foods are out of place in most herofi or highfy.
The first reason to avoid artifacts of our post-renaissance worldwide culture is atmosphere. If you want your reader to immerse in your medievalesque world, don’t keep swatting them in the face with things that don’t feel medieval. If you want a feel of the Orient, don’t bring in New World stuff and if you want a Mesoamerican ambiance, keep European stuff out of the mix.
Particularly, I recall objecting to characters eating cinnamon cookies in a northern mountain culture, in a ms I critted for a workshop. The author’s attitude was that they were technologically possible, so why not? My objection was that “cookies” were unnecessarily shoving 21st century America into a world so alien it didn’t have dogs or horses. The cookies weren’t necessary to the plot. They were merely cosmetic, and in this case the wrong cosmetics. I mean, in the same village, you might as well serve tamales or have the children play basketball.
They’re just as atmospherically wrong, though technologically possible. They’re just not technologically plausible.
“Cookie” is a specifically American and modern (last couple of centuries) word. “Sweet biscuits” or “sugarcakes” could have served the same purpose without swatting the reader out of immersion.
But are they technologically possible? The world described was a limited landscape, with nothing mentioned colder or warmer than a temperate zone, no outside cultures or people, nothing foreign. In what tropical enclave were the cinnamon trees, the sugar cane, and the coffee beans grown? In what tropical land did their wild ancestors evolve and fall under domestication — or at least human harvesting? Only one monolithic culture exists.
Now, we certainly hope that when you sit down to world-build that you will consider the history of your world, however Terran, long enough to decide what is and is not possible in plant technology as much as you would consider whether or not you’re going to have petroleum refineries.
The usual English speakers reading this, especially Americans, need to realize that the variety of foods easily available to us is unprecedented in the history of the world and is a result of our transportation technology, especially in food-handling. Most people below the middle class in Europe rarely ate meat — once or twice a month — until steamships and mechanical refrigeration let Argentinians ship beef to England and France. Before then, they only shipped the hides for leather and threw the carcasses to the dogs or whatever poor person wanted them. In the early 1800s in Southern California, any hungry person could kill a steer out in the pastures for food, provided they skinned it and hung up the valuable hide for the owner. The meat had no market value until 1849.
Undoubtedly, you’ve heard that spices used to be worth their weight in gold in Europe after being processed and shipped halfway across the world.
So there’s more than an artistic reason not to serve scalloped potatoes in your peasant cottage that otherwise is medieval European.
Many writers, when world-building, are uncomfortable moving out of the temperate zone. This means that they need to eliminate all the tropical or tropically derived foods. If hardly one person a century tries (or survives) crossing the Rock Waste to the west, and there is no easy passage across the seas east and south, they aren’t going to have common cheap imports of spices and tropical foods, nor are they likely to import the culture of strange plants from the wrong latitudes. They’re going to have a settled agricultural package. As farmers usually aren’t big gamblers, there is going to have to be a big incentive for them to take up growing something arcane like apples or asparagus.
Oh, yeah. Apples you can eat out of hand aren’t something where you throw the seeds at the ground, wait three years, and harvest. They’re grown by the arcane system of grafting, where you grow a rootstock sapling, cut off its upper parts, then attach a branch of a different variety to live on the stock and feed it, and produce its known kind of fruit. That’s why apples were domesticated so late, c. 2000 BC. Until then all you get are little sour wild crab apples, that are only good for fermenting into cider.
One thing you need to consider is the climate groupings of crops. The reason one area developed a lot of different grains is there were lots of wild grasses the pre-farmers liked to eat. Ditto lots of varieties of beans, or citrus fruit. You need to remember that before modern technology (understanding of horticulture) developed corn that would grow in Iowa, it was restricted to its native tropics, where the precursor to maize, teosinte, had cobs half an inch long. It took the original Americans long centuries to breed strains that would grow farther and farther north, after breeding them bigger and bigger so anyone cared to bother growing it.
So, in a well-built world, if you don’t have a good connection to a land where teosinte would rationally grow, you’re not going to have maize, so no corn fritters, hominy grits, or corn bread for your hero.
Technically, if the culture has maize, there’s no scientific reason your heroes can’t spend their downtime quaffing mead and eating — buttered popcorn.
The reason for having or not having is an artistic one.
Why do you want them to have popcorn?
1) “Because no one ever does.” This is weird for weird’s sake. The presence is cosmetic and the purpose, really, is to make the reader say how clever the writer is for doing this. These are all reasons to put walnuts in place of the popcorn.
2) “Because it’s so funny!” If you are writing comedy, this is a big yes. You might even go for pink and green kettle corn. Otherwise, it’s the wrong kind of laugh for tension relief: it pulls the reader out of the story.
3) “It’s a thing I do to signal this place has connections with our world.” Whether a lost Terran colony or someone trading through space-time gates — it’s a good thing to do. Just do have more than one. Otherwise, it will look like a mere faux pas of world-building.