Lee’s eating habits are not just a function of her allergies, though. She likes that eating the same thing makes grocery shopping simpler, brings consistency to her sometimes chaotic schedule, and made it less likely she’d spend the money at the “$12-salad place” near her previous office. Besides, she really likes the things she brings. “I’m not eating, like, a PB&J every day,” she says. “I try to make it taste good and interesting.” (I did not tell Vern Loomis what Lee apparently thinks of his lunch.)

Chloe Cota, a computer engineer in New York City, does not have as strict a lunchtime regimen as others described in this story, but she has noticed that when her company brings in catered lunch, she always picks a salad when it’s available. She came to think of this default selection as reducing her “cognitive overhead”—a way of not expending mental energy on something that wasn’t a high priority for her.

“Lunch variety doesn't really matter to me,” she says. “I would be perfectly happy to eat the same Caesar salad or peanut-butter-and-jelly sandwich every day.” Similarly, she has devised a standard “work uniform” (one of her many pairs of black leggings, plus a T-shirt), which helps streamline her morning routine. She says she took inspiration from tech moguls such as Steve Jobs and Mark Zuckerberg, who essentially automated their own daily attire decisions in the name of reducing cognitive overhead.

The salad station, Cota says, is also an opportunity for her to practice “mindful eating,” something she started doing as part of her recovery from an eating disorder she developed in high school. She says it helps to know that the foods available to her in that moment are ones she knows she likes, which “short-circuits that whole negative space in my brain where I might get back into those disordered behaviors.”

For some people, the repetition in their daily food preparation is in the meals they make for other people. Ambreia Meadows-Fernandez, a 26-year-old writer in Cheyenne, Wyoming, cooks the same meal—“a meat and rice,” sometimes with some vegetables—for her 3-year-old son most nights of the week. “It made it simple in a way that there was less stress about what to give him,” she says. He usually gets a peanut-butter-and-jelly sandwich for lunch, and doesn’t seem to mind the lack of variety.

Of course, most people around the world who eat the same thing every day aren’t doing so voluntarily. “I would say most people most of the time have little choice in their staple,” says Paul Freedman, a historian at Yale and the author of Ten Restaurants That Changed America. “If they live in a rice culture, they will have rice for every meal; ditto potatoes.” The cooking fat used—say, butter or ghee—generally remains the same as well.

The variety, Freedman says, usually comes from “relishes,” the food-anthropology term for flavor-adding ingredients such as spices, vegetables, and modest amounts of meat (like bacon). “This staple + fat + relish combination is what dominated eating in traditional peasant cultures,” he wrote in an email.