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There’s no good reason you can’t eat a chicken-parmesan hoagie for breakfast. That’s what I decided last year when I woke up one morning, hungover and ravenous, craving the sandwich’s very specific combination of fried chicken cutlet, melted mozzarella, and tomato sauce. “Breakfast food,” as a category, suddenly felt like my middle school’s dress code: unnecessarily prim and preordained by people whose rules I should no longer heed.

I wrestled with the idea while summoning the wherewithal to leave bed. Why did a breakfast chicken parm seem so louche to me when an egg sandwich—a similar combination of protein, dairy fat, grease, and carbohydrates—seemed so benign? If I marched up to the counter at my local bagel shop, which makes chicken-parm sandwiches for lunch, could I even order one at nine in the morning? If I succeeded, would it open a Pandora’s box of forbidden-food hedonism from which I could never return? Why was breakfast food even breakfast food in the first place?

My pep talk to myself was for nothing. When I ordered, the counter attendant didn’t seem to care about my brave departure from the useless strictures of American breakfast. I wolfed down my sandwich with unrestrained joy. Since childhood, I’d mostly disliked cereal, oatmeal, and yogurt, which always put me at odds with breakfast as a concept. Now I knew I had been right all along. Any insistence that only certain foods are appropriate for the day’s first meal was silly.

“Breakfast food” might be an arbitrary concept in America, but it’s a distinct one: cereal with milk, a cup of yogurt, eggs, muffins, fruit, oatmeal, juice. Maybe pancakes or waffles on the weekend, if you have some extra time. There are some regional variations, like bagels or biscuits, but the menu tends to be far more predictable than lunch or dinner. And although American breakfast isn’t nutritionally or philosophically cohesive, how the country goes about its morning meal isn’t a mistake. Modern breakfast in the United States tells the story of more than a century of cultural upheaval.

American breakfast begins in Europe, which provided the food norms imported by early colonizers. There, the day’s first meal had emerged from centuries of prohibition under the Catholic Church. “There was a period of time in England and western Europe where eating breakfast was sort of tied to gluttony,” says Heather Arndt Anderson, the author of Breakfast: A History. That all changed with the Protestant Reformation, when morning sustenance became more broadly permissible, if not all that exciting, or even distinct from everything else people ate. Lack of refrigeration meant the meal was usually sour and tepid. In Germany, beer soup was common.

In early America, breakfast remained a matter of convenience for most people: bread; preserved meats; repurposed leftovers; and things, like eggs, that were easy to prepare and regularly available to rural families, Arndt Anderson says.

According to Krishnendu Ray, a professor of food studies at New York University, that’s consistent with how much of the world still approaches the day’s first meal. “Poorer people everywhere, especially in places like India and China, eat the same kind of food for meal after meal,” he says. “The strict differentiation of meals is partly an American thing, but partly a thing of upward mobility.” Breakfast food, as a concept, is a luxury. As colonial America developed into a more robust culture with distinct class markers, breakfast started to change with it.

At first, this evolution was slow. America was a growing country, but technological limitations in both communication and food preparation meant that the morning meal was a largely regional concern, dictated by crops and livestock, as well as the previous day’s leftovers. In at least one sense, a college student waking after a night out and scarfing down two slices of unrefrigerated pizza rapidly aging in their delivery box is actually just participating in what breakfast has historically meant to billions of people.

The alarm with which Americans now commonly regard eating day-old, unrefrigerated food started to develop as the Industrial Revolution changed food preservation, the workday, and cultural conceptions of health. Arguably no one was more directly responsible for these shifts than the Kellogg brothers, who developed Corn Flakes in the late 1800s as an outgrowth of John Harvey Kellogg’s work at his Battle Creek Sanitarium, in Michigan. Kellogg was a doctor and an adherent of the Seventh Day Adventist Church, which advocated a bland, vegetarian diet and abstention from things like caffeine and alcohol.

Although historical tellings tend to emphasize that Corn Flakes were designed to steer people away from sexual thoughts, Arndt Anderson says they also served other Adventist aims. “It was tied to the health benefits of having a little grain to get your morning constitutional,” she says. Kellogg was “really interested in getting people to poop.”

Corn Flakes might not have been so pivotal without a few other results of industrialization: the proliferation of advertising, and the rapidly expanding accessibility of refrigeration (for milk) and cheap sweeteners (to make anti-masturbation Corn Flakes marketable to children). The first half of the 20th century is when breakfast’s class elements start to take hold in the U.S., Ray says. Refrigeration was a luxury, and although the ingredients in cereal might be cheap and nutritionally hollow, brand-name versions have always been pricey. “The most expensive part of cereal-making is shoving it down people’s throats by advertising,” he explains. “I don’t think cereal would have been successful without the massive propaganda of the industry.” A morning bowl of Cheerios—and the ability to buy special foods, just for breakfast—became a signal of sophistication.

Cereal, along with many other packaged breakfast foods, had another factor in its favor: how technological innovation changed labor in America. “The Industrial Revolution really standardized the times at which people work,” says Arndt Anderson. That also helped standardize when they ate, and how much time they had to prepare and consume food. Formalized labor also lengthened commutes and, eventually, integrated women—formerly housewives or domestic servants—into the workforce in enormous numbers after the Second World War.

With these shifts came the eventual displacement of traditional breakfast foods, like bacon and eggs, from the workweek to weekend brunch. Although long considered quick and convenient, these foods “are relatively more labor-intensive in the morning,” Ray says. Industrially produced breakfast products, like cold cereal, yogurt, and instant oatmeal, dramatically reduced the time and effort required of working women to feed their family, and the skyrocketing sugar content and colorful mascots made them an easy sell to most kids (and, therefore, most harried moms).

In the 1980s, nutritional scaremongering over fat consumption helped cement sweetened, industrialized grain and dairy products as morning go-tos. Although America’s relationship with dietary fat has moderated in recent years, moralistic fears over whether any given breakfast is “good” aren’t easily parsed, and the 10 minutes people might have to slam a Chobani before work aren’t the ideal time to reconsider the often-conflicting evidence. Eggs, for instance, have been hyperbolically hailed as both a nutritionally complete superfood and a heart attack in a shell. But Ray says there’s scant dietary explanation for the way we eat in the morning now: “There’s no good reason why we should have so much sugar in the morning, or something cold.” In fact, the value of eating breakfast at all isn’t exactly settled science. Its role as the “most important meal of the day”? All marketing.

Even though the average American conception of breakfast is unnecessarily stringent, it’s unlikely to loosen anytime soon. Breakfast’s hasty preparation and Americans’ muddled understanding of confusing nutritional news make the meal resistant to change. “Food is a domain of habit,” Ray says, and that’s particularly true for the morning meal. “People are just waking up, and they need their caffeine-delivery system and they need their cereal and they don’t want too much thinking about it.” He has noticed American-style breakfasts spreading to places like India and China in much the same way they took over this country during the 20th century: as a mixture of convenience and class marker while labor forces modernize.

It took the Industrial Revolution, a couple of world wars, and women’s lib to get the United States to the breakfast menus it has today, and it would likely take a similarly seismic shift to free Americans from their cereal or yogurt routines in any meaningful way. But that doesn’t mean you can’t free your mind, as long as you can find a nearby sandwich shop willing to make anything on its menu all day.

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