The Psychology Of Why So Many People Hate Eating Leftovers

Money, mould, monotony — they all play a role in your attitude about leftover food.
Steven Puetzer via Getty Images

Some people are bad about eating leftovers, their refrigerators filled with takeout containers and Tupperware containers of dubious provenance. For others, leftovers are an opportunity ― they diligently eat them and may even strategically cook large meals with the intention of having leftovers all week.

Why do people respond so differently to leftovers? Is it a class issue, with the upper class snubbing leftovers as being below them? Or perhaps some people get nervous about eating old food? Turns out, it’s all those things and more. Talking with experts, we learned that one’s approach to leftovers depends on a variety of factors including economics, food safety and even sustainability.

How Money And Mould Play A Role

A person’s economic situation may play a huge role in their approach to leftovers, determining whether they eat them regularly or throw them out. For some people, eating leftovers is a necessity; they need to make those food dollars last, explained Catherine Coccia, associate professor of dietetics and health at Florida International University. However, other folks may be economically stable enough to afford to eat other foods and throw away leftovers.

Anxiety over food safety may be another factor, and it’s closely linked to anxiety about spending or wasting money on food. Some people feel they’re “racing against rot,” explained Helen Zoe Veit, associate professor at Michigan State University and author of “Modern Food, Moral Food.” Many are nervous about whether food is still safe to eat ― anyone who has had food poisoning can relate. But it can depend on the food.

“Meat and especially fish leftovers tend to elicit more anxiety regarding food poisoning than do non-meat foods,” explained Adam Wenzel, associate professor of psychology at Saint Anselm College. He recommends the 2-2-4 rule: “Within two hours of preparation, store leftovers in the refrigerator in a shallow, 2-inch dish, and consume within four days.”

Cooking Confidence Is Key

People may also worry about what to do with leftovers. Sure, we’ve all been trained to become wizards with Thanksgiving leftovers, but during the rest of the year we’re not always full of great ideas.

If someone is comfortable cooking, they may be able to effectively reuse leftovers, Veit explained ― they can just toss them into a pot and whip up a soup and feel productive about it. But if a person is lacking confidence or skills in their cooking abilities, they may be gripped with fear and less inclined to use up those leftovers.

Veit also pointed out that people tend to have varied diets ― Chinese food one night, spaghetti the next, a hamburger on Sunday ― and assembling a full meal from those leftovers might be a challenge. And there’s not a lot of room for error when it comes to re-preparing leftovers ― for instance, there isn’t much you can do to improve a dressed salad after it’s gotten soggy.

Sure, we all know what to do with Thanksgiving leftovers. But what about the rest of the year?
Sure, we all know what to do with Thanksgiving leftovers. But what about the rest of the year?

Some People Are Wired To Enjoy Monotony, But Many Aren’t

The monotony of eating the same food every day plays a big role in one’s approach to leftovers, and it’s not something that can be easily proven by science. “We seem to be ‘wired’ to want variety in our diets,” Wenzel said, “[which] may be important for ensuring we consume a balanced diet.”

But for others, eating the same food all week can provide a sense of control that eases anxiety. For folks on a specific diet, making a big batch of foods that agree with them removes the temptation to reach for bad choices out of desperation. And if you’re about to have a busy week, meal planning can take a lot of the stress out of your schedule.

Attitudes Toward Leftovers Have Changed Over Time

Historic attitudes to leftovers have also influenced us. Veit explains that at the beginning of the 20th century, people just expected to eat leftovers most days ― it was what you ate for your next meal. The concept of leftovers began to develop when refrigerators were introduced into people’s homes in the 1920s and ’30s, which meant that food could last longer. Initially, wealthier families owned fridges, so having leftovers was actually a sign of prestige. But over time, fridges became more common in people’s homes and leftovers lost their lustre.

After the food scarcity of the Great Depression and rationing during World War II, leftovers became all the rage for three decades, Veit said. Cookbooks, in general, emphasised creativity and taught home cooks how to incorporate their leftovers into other foods. But later on, this positive outlook on leftovers dissipated as food became cheaper and incomes rose, Veit explained. Eating leftovers weren’t considered as economically or morally necessary as they were in the past; they were seen as something seen closer to garbage than food.

As Portion Sizes Get Bigger, We’re Burdened With More And More Leftovers

In recent decades, restaurants have increased their portion sizes, which produces a larger amount of leftovers when people can’t finish their heaping plateful.

Researchers are starting to look at how having leftovers may impact people’s behaviour towards other foods. Linda Hagen, associate professor of marketing at University of Southern California, and Aradhna Krishna, a professor at University of Michigan, conducted an experiment giving two groups two different-sized cookies, large and small, and told to eat a certain amount of the cookie. Afterwards, they gave both groups a bag of cookies and said they could eat as many as they wanted.

The study found that participants with the larger cookies, and thus the biggest leftovers, ended up eating more cookies than the other group. They also worked out less than the small-cookie group. Hagen theorised that people saw the larger amount of leftovers and perceived they had eaten less, so they felt that they could indulge more and did not need to exercise as much. While this is one experiment and more studies need to be undertaken, it’s suggestive that having leftovers may impact food choices and amount of food consumption later on.

On The Plus Side, Leftovers Can Help Save The Planet

But one prevailing trend that researchers are seeing right now is the rise of sustainability when it comes to leftovers.

“Some people are growing to understand that food production is resource-intensive from soup to nuts,” Veit said. Throwing away food is wasting all the resources that went into making and growing the food. And Americans throw a lot of it away ― the United States Department of Agriculture reports 133 billion pounds of food were thrown away in 2010. Eating leftovers is one way of minimising food waste.

As sustainability becomes more mainstream, it still remains to be seen whether leftover-haters will be motivated to change their outlook.