Irma Rombauer said she wrote The Joy of Cooking with “one eye on the family purse.” Maybe it’s not surprising, then, that the original 1931 edition had so much to say about leftovers. Rombauer carefully inventoried all the recipes in the book that could serve as vessels for leftovers, and she enthusiastically detailed her favorite all-purpose techniques, such as folding chopped leftovers (it didn’t really matter what) into waffle batter or mixing them with cream sauce and stuffing them into hollowed-out vegetables.

These tips resurfaced in editions of The Joy of Cooking published well after the Depression, but the tone on leftovers steadily shifted. In the early 1950s, Rombauer noted for the first time that too much budget-minded cooking could incite “family protest,” and she urged cooks not to think of leftovers as dreary. By the 1963 edition, the first published after Rombauer’s death, her daughter Marion Rombauer Becker drastically condensed the leftovers section and started it with a joke: “‘It seems to me,’ the minister said, after his new wife placed a dubious casserole on the table, ‘that I have blessed a good deal of this material before.’”

The truth was that by the 1960s leftovers were becoming a joke to a lot of people, with a grumbling husband and a mystery casserole playing stock roles. That humor was a direct result of abundance. In the postwar era, a historically anomalous food economy was coming to define American culture, as the cost of food relative to income plummeted and even the poorest Americans were less desperate for calories than they had ever been. Leftovers were coming to seem less like a signal of household abundance and more like a drag. The best way to serve them, another joke went, was to somebody else.

Leftovers hadn’t been a joke to earlier generations of Americans. In the 19th century, in fact, Americans had rarely talked about leftovers as a discrete category of food at all. Cookbook authors then occasionally discussed “fragments” or “réchauffés,” but using up leftover food was so fundamental to everyday cooking and eating that most people didn’t have a special name for it. Breakfast was usually a meal of leftovers, the meat or beans or pie (or anything, really) left from the day before. Simmering stockpots were crucial catch-alls for kitchen scraps. Techniques like pickling, potting, smoking, and salting defined 19th-century cuisine because, before reliable refrigeration, cooking and food preservation were barely distinguishable tasks. Americans turned leftover milk into an array of longer-lived dairy products, and they drank whiskey and hard cider by the gallon in part because alcohol kept leftover grains and fruits edible long after they were in season. Foods that weren’t preserved had to be eaten quickly.

But by the turn of the 20th century, Americans’ relationship with leftovers was changing. Iceboxes were becoming standard features in middle-class homes, and early electric refrigerators soon followed. Refrigeration made it possible to keep highly perishable foods edible for days simply by keeping them cool, and that prompted an enormous shift in American cuisine. A whole arsenal of home preservation techniques, from cheese-making to meat-smoking to egg-pickling to ketchup-making, receded from daily use within a single generation. The unique properties of coldness as a preservative meant that the same meal could reappear in virtually the same form, day after day. It was no accident that the term “left-overs” was coined in this era, or that one of the first cookbooks devoted to them, the 1910 Left-Over Foods and How to Use Them, was commissioned by a refrigerator company.

The cover of 1918’s Left Overs, or Economy in the Kitchen. The term “left-overs” had been coined earlier that century. (Special Collections, Michigan State University Libraries)

But even as refrigeration turned leftovers into a distinct culinary category, they still weren’t anything to laugh about. Americans in the early 20th century spent about 40 percent of their incomes on food, on average, and poor people spent even more. Diseases of malnutrition such as pellagra and rickets plagued the poor, and urban tenements were filled with families who never had the luxury of food uneaten between one meal and the next. Middle-class and wealthy Americans were often visibly bigger and taller than poor and working-class people because they had had access to ample calories during their childhood growth spurts. In this era, having leftovers and an icebox to put them in were status symbols.

Leftovers took on moral urgency in World War I, when the United States launched its first formal international food-aid program. Intended to provision European allies in regions where the war had upended food production and distribution, the initiative included a home-front conservation campaign focused on getting Americans to eat their leftovers. Propaganda instructed housewives to use up every crumb and to cook leftover-incorporating dishes such as goulashes and casseroles.

In their zeal to send whatever food they could to war-torn Europe, a lot of individuals went further still. Some said restaurants should resell the uneaten food scraped from dirty plates. Others argued that it was immoral to keep pets because they ate food that could be used to feed hungry Belgian babies. (A neutral country invaded by Germany at the beginning of the war, Belgium was, to Americans, the prototypical victimized country.) That was true, at least in theory; at the time, American dogs and cats lived mainly on human food past its prime, such as stale bread and souring milk. In wartime, some Americans actually killed their pets rather than continue feeding them leftovers, and newspapers across the country celebrated them as patriots.

Leftovers’ patriotic glamour dimmed in peacetime, however, and by the mid-1920s Americans were openly discussing the “problem of leftovers,” a new source of annoyance as food prices fell and home refrigeration became almost ubiquitous. As abundance democratized leftovers, wealthy people increasingly went out of their way to emphasize that they rarely ate them. For instance, some white southerners publicized the fact that they sent their domestic servants home with the leftovers from their own dinners. Never mind that those same employers used that practice—“pan-toting,” as it was called—to justify wages whose miserliness could not possibly be made up for by somebody else’s leftover food.

But another wave of pragmatism set in during the Depression, when, at the same time that tens of thousands of Americans were investing in The Joy of Cooking’s economical cooking advice, radio broadcasts sponsored by the U.S. Department of Agriculture reminded listeners of the crucial importance of eating leftovers in lean times. “Of course, if you’re the wife of a multimillionaire, you probably won’t bother much about leftovers,” winked one broadcast. For everybody else, making the most of leftovers was both important and potentially pleasurable. And that pleasure came from creativity.

In fact, the economic imperatives of the Great Depression helped to usher in a golden age of leftovers, a three-decades-long stretch that was inspired by the family budget but sustained by aesthetics. Then, if it was a good thing to reheat leftovers, it was even better to mix them with sauce and sculpt rice rings around them. Transformation was key. Leftovers of all kinds could be hidden in a potpie, blanketed in crepes, chopped up and molded into meat loaf.

In the hands of an imaginative chef, leftovers were scarcely recognizable as such when they made it back to the table, but the goal was less deception than alchemy. One recipe for leftover carrots, for example, called for pureeing them, mixing them with breadcrumbs and seasonings, then reshaping them into long cones topped with parsley so that they resembled, of all things, carrots—it was like painstakingly painting wood in faux bois. The elaborateness of such culinary stunts made the point that as the ultimate test of a cook’s skill and imagination, leftovers, maybe even more than first-run foods, could be art.  

But leftovers’ glory didn’t last. By the 1960s, an enthusiastic approach to leftovers was coming to seem a little pathetic. The genre-busting leftover recipes of the previous three decades—the “Beef Put-Togethers” and the “Ham Banana Rolls with Cheese Sauce” and the gelatin salads quivering with “remnants from the relish tray”—felt off-putting rather than exciting. Leftovers were becoming a joke. A gelatin salad filled with leftovers might feed a lot of people, joked Peg Bracken, the author of the 1960 satire I Hate to Cook Book and its sequels, but that was only because so few went back for seconds.

A big reason for the growing aversion to leftovers was that by the 1960s Americans in large numbers were financially secure enough not to have to worry too much about wasting food. Americans were spending only about a quarter of their incomes on food by then, and that percentage was falling every year. All the scraping and planning that had to go into reincarnating leftover egg whites or boiled vegetables seemed a waste of time when those foods were cheap to start with. Don’t bother, Peg Bracken advised readers: “When in doubt, throw it out.”

In fact, leftovers have always been uncomfortably close to garbage, and that proximity became glaringly obvious when leftovers lost both their economic and moral urgency. Facing the daily cost-benefit analysis of repackaging old meals for a reluctant family, home cooks increasingly just threw their leftovers away, albeit sometimes after letting them age in the back of the fridge for a while. Throwing away edible food was a prerogative of financial security, and Americans began doing it an awful lot.

And perhaps it was that very cavalierism towards waste, which in many ways defined American attitudes towards food for the rest of the 20th century, that is finally bringing leftovers back into fashion now.

Today, Americans spend just over 10 percent of their incomes on food, on average—less than any people in the history of world. But food waste has come to seem unaffordable in other ways. More Americans are becoming aware of the externalized costs that go into food, from the water needed to grow it to the fuel required to transport it, cool it, and cook it, to the questionable government policies that keep certain crops cheap and the wages paid to farm workers miniscule. Gleaning and scavenging and scrimping have become righteous statements in some quarters. Foraging, meanwhile, has been elevated to high cuisine.

And then there’s taste. Some things, such as fish and salad greens, are clearly superior when they’re absolutely fresh. But a lot of other foods, such as soups and curries, taste better a day or two or three after they were made. It’s an argument chefs have been making for a long time, and it seems to be finding new purchase on mainstream habits—leftovers might actually be entering another golden age. The Joy of Cooking, now in its online iteration, encourages the repurposing of leftover meats in tikka masala, Vietnamese bún bowls, and molé. Once again, the cookbook is effusing about the possibilities of leftovers—this time almost entirely from the perspective of pleasure.