Eating in Front of a Mirror Can Make Junk Food Less Delicious


Nutrition science is a complicated, ever-changing animal. Some experts believe fat is the enemy, while others suggest eating more of it. The same is true for carbs, alcohol, and caffeine. It’s hard to know what’s healthy and what’s not, although there are some exceptions. A cheeseburger, for example. A piece of chocolate cake. A bag of potato chips. A bowl of ice cream. We eat these foods knowing that they’re not good for us. Now, one researcher says that recognizing that guilt can actually ruin the taste of the food.

Behavioral scientists have something called the objective self-awareness theory, which basically says that seeing yourself—whether physically in a mirror or photograph or mentally through writing—forces you to think about what you're doing and why. Studies have shown that this heightened self-awareness can actually change behavior. People confronted with their own image are less likely to cheat on tests, act on sexual impulses, and stereotype other people.

Marketing expert Ata Jami wondered if raising people’s self-awareness could change the way they ate. Would eating junk food be less enjoyable for people who had to watch themselves do it?

Jami ran four experiments on hundreds of undergraduate volunteers at the University of Utah. All the volunteers were told they would be taste-testing new products. 

In the first study, participants were offered a choice between two chocolate bars: one described as “healthy” and the other as “tasty.” They were then left alone in a room with or without a mirror to taste the chocolate. After they finished the chocolate, the volunteers filled out a survey rating the chocolate’s taste. People who had picked the “tasty” chocolate didn’t like it very much—but only when they had to eat it in front of a mirror. Volunteers who sat in rooms without mirrors rated the unhealthy chocolate bar just fine. And mirror or no mirror, the “healthy” chocolate got high marks from every taster.

The second and third studies focused on responsibility. Some study participants were randomly assigned to taste either brownies or dried fruit. Others were told to rank a list of healthy and unhealthy snacks in order of their preference. Then they were randomly assigned brownies or dried fruit anyway, with a cover story that the experimenters had “run out” of the other choices. Some people had ranked brownies or dried fruit highly and actually got what they wanted. Everybody else just ate what they were given.

Choice proved to be an important element. People in mirrored rooms who chose to eat brownies gave the brownies a low grade. But everything tasted just fine to the taste-testers who had asked for something else. In short, people who had to watch themselves eat only disliked eating brownies when it had been their idea in the first place. 

Jami has a theory about why the taste of junk food suffers. In an upcoming paper in the Journal of the Association for Consumer Research, he explains that awareness of our poor choices makes us uncomfortable. In the absence of any obvious cause for the discomfort, he says, we tend to blame whatever’s in front of us. In the first three experiments, study participants had been told to pay attention to how the food tasted. It's only natural that the unpleasant feelings manifested as flavor issues.

To test this idea, he added one more element to the last study: music. Study participants were divided into two groups. Jami piped music into all of the study rooms. Half of the volunteers proceeded as usual with the mirrored taste tests. The other half were told that the experiment was trying to test whether or not music could affect their feelings. All participants got to choose between chocolate cake and fruit salad.

The results for the first group matched those of the other three studies: mirror + junk food = ick. People who ate healthy food thought their food tasted fine, as did people who ate junk food without a mirror. But people in the second group had been primed to pay special attention to the music. Sure enough, volunteers in the mirror/music/cake group rated their cake as perfectly tasty. Jami believes they attributed their unease to the music instead. 

Now, there are a few caveats to consider before we conclude that adding mirrors to our dining rooms will make us all thin. First, Jami didn’t measure how much people ate. He just measured how bad it made them feel. For all we know, that uneasy feeling could prompt us to eat more.

Secondly, “healthy” and “unhealthy” are kind of fluid terms, especially in this study. For example, the “healthy” and “tasty” chocolate bars in the first experiment? Those were all the same chocolate bars. The experimenters just called them different things. So it’s not necessarily that eating unhealthy food makes us uncomfortable—it’s eating food we think is unhealthy.

Lastly, Jami is not sure how it will work with actual meals, since people often eat healthy and unhealthy food together. If dinner is a cheeseburger and a salad, does the mirror make only the cheeseburger taste bad? Does the salad also take a hit? Do they both taste fine? Nobody knows.

The Science Behind Why We Crave Loud and Crunchy Foods

A number of years ago, food giant Unilever polled consumers asking how the company might improve their popular line of Magnum ice cream bars. The problem, respondents said, was that the chocolate coating of the bars tended to fall off too quickly, creating blotches of sticky goo on carpeting. Unilever reacted by changing the recipe to make the chocolate less prone to spills.

When they tested the new and improved product, they expected a warm reception. Instead, they got more complaints than before. While the updated bar didn’t make a mess, it also didn’t make the distinctive crackle that its fans had grown accustomed to. Deprived of hearing the coating collapse and crumble, the experience of eating the ice cream was fundamentally changed. And not for the better.

Smell and taste researcher Alan Hirsch, M.D. refers to it as the “music of mastication,” an auditory accompaniment to the sensory stimulus of eating. “For non-gustatory, non-olfactory stimulation, people prefer crunchiness,” he tells Mental Floss. Humans love crunchy, noisy snacks, that loud rattling that travels to our inner ear via air and bone conduction and helps us identify what it is we’re consuming. Depending on the snack, the noise can reach 63 decibels. (Normal conversations are around 60 dB; rustling leaves, 20 dB.)

When we hear it, we eat more. When we don’t—as in the case of Magnum bars, or a soggy, muted potato chip—we resort to other senses, looking at our food with doubt or sniffing it for signs of expiration. Psychologically, our lust for crispy sustenance is baked in. But why is it so satisfying to create a cacophony of crunch? And if we love it so much, why do some of us actually grow agitated and even aggressive when we hear someone loudly chomping away? It turns out there’s a lot more to eating with our ears than you might have heard.


The science of crunch has long intrigued Charles Spence, Ph.D., a gastrophysicist and professor of experimental psychology and head of the Crossmodal Research Laboratory at the University of Oxford. Food companies have enlisted him and consulted his research across the spectrum of ingestion, from packaging to shapes to the sound chips make rustling around in grocery carts.

“We’re not born liking noisy foods,” he tells Mental Floss. “Noise doesn’t give a benefit in terms of nutrition. But we don’t like soggy crisps even if they taste the same. Missing the sound is important.”

In 2003, Spence decided to investigate the sonic appeal of chips in a formal setting. To keep a semblance of control, he selected Pringles, which are baked uniformly—a single Pringle doesn't offer any significant difference in size, thickness, or crunch from another. He asked 20 research subjects to bite into 180 Pringles (about two cans) while seated in a soundproof booth in front of a microphone. The sound of their crunching was looped back into a pair of headphones.

After consuming the cans, they were asked if they perceived any difference in freshness or crispness from one Pringle to another. What they didn’t know was that Spence had been playing with the feedback in their headphones, raising or lowering the volume of their noisy crunching [PDF]. At loud volumes, the chips were reported to be fresher; chips ingested while listening at low volume were thought to have been sitting out longer and seemed softer. The duplicitous sounds resulted in a radical difference in chip perception. It may have been a small study, but in the virtually non-existent field of sonic chip research, it was groundbreaking.

A view inside a potato chip bag

For Spence, the results speak to what he considers the inherent appeal of crunchy foods. “Noisy foods correlate with freshness,” he says. “The fresher the produce, like apples, celery, or lettuce, the more vitamins and nutrients it’s retained. It’s telling us what’s in the food.”

Naturally, this signal becomes slightly misguided when it reinforces the quality of a potato chip, a processed slab of empty calories. But Spence has a theory on this, too: “The brain likes fat in food, but it’s not so good at detecting it through our mouths. Noisy foods are certainly fattier on average.”

Fatty or fresh, raising decibels while eating may also have roots in less appetizing behaviors. For our ancestors who ate insects, the crunch of a hard-bodied cricket symbolized nourishment. In a primal way, violently mincing food with our teeth could also be a way to vent and dilute aggression. “There are some psychoanalytic theories related to crunchiness and aggressive behavior,” Hirsch says. “When you bite into ice or potato chips, you’re sublimating that in a healthy way.”


All of these factors explain why crunch appeals to us. But is it actually affecting what we taste?

Yes—but maybe not the way you’d think. “Sound affects the experience of food,” Spence says. “The noise draws attention to the mouth in the way something silent does not. If you’re eating pâté, your attention can drift elsewhere, to a television or to a dining companion. But a crunch will draw your attention to what you’re eating, making you concentrate on it. Noisy foods make you think about them.”

That crunch can also influence how much food we consume. Because noisy foods tend to be fatty, Spence says, they’ll retain their flavor longer. And because the noise reinforces our idea of what we’re eating, it affords us a sense of security that allows us to keep consuming without having to look at our snack—not so important in a brightly-lit room, but crucial if we’re in a dark movie theater. “It becomes more important when you can’t see what you’re eating,” Spence says.

Thanks to this hard-wired feedback, the snack industry has made it a priority to emphasize the sounds of their foods in both development and marketing. In the 1980s, Frito-Lay funded extensive work at a Dallas plant that involved $40,000 chewing simulators. There, they discovered the ideal breaking point for a chip was four pounds per square inch (PSI), just a fraction of what we might need to tear into a steak (150 to 200 PSI). The quality and consistency of the potatoes themselves is also key, according to Herbert Stone, Ph.D., a food scientist who has worked with companies on product development. “Too thick, too hard, and people don’t like them,” Stone tells Mental Floss. “Too thin and they just crumble.”

The right potato sliced at the right thickness with the right oil at the right temperature results in a solid chip—one resilient enough to make for a satisfying break when it hits your molars, but vanishing so quickly that your brain and body haven’t even processed the calories you’ve just taken in. “If they pick it up and put it in the mouth and the crunch is not what they expect, they might put it down,” Stone says. “It’s about expectation.”

A shopper examines a bag of potato chips

Walk down the snack aisle in your local supermarket or glance at commercials and you’ll find no shortage of claims about products being the boldest, crunchiest chip available. For years, Frito-Lay marketed Cheetos as “the cheese that goes crunch!” Even cereals try to capitalize on the fervor, making mascots—Snap, Crackle, and Pop—out of the sound their Rice Krispies make when submerged in milk. One ad for a brand of crisps drew attention for “cracking” the viewer’s television screen.

For most consumers, the promise of sonic flavor will draw their attention. But for a small number of people diagnosed with a condition dubbed misophonia, the sound of a co-worker or partner crunching on chips isn’t at all pleasurable. It’s insufferable.


According to Connecticut audiologist Natan Bauman, M.D., the average noise level of someone masticating a potato chip is between 25 to 35 decibels. (Other sources peg it as closer to 63 dB when you're chewing on a chip with your mouth open, or 55 dB with your lips closed.) When you hear your own chewing, the sound is being conducted both via the air and your own bones, giving it a distinctively unique sound. (Like talking, hearing yourself chewing on a recording might be troubling.)

For someone suffering from misophonia, or the literal hatred of specific sounds, it's not their own chomping that's the problem. It's everyone else's.

When we chew, Bauman says, the auditory cortical and limbic system areas of our brain are lighting up, getting information about freshness and texture. But people with misophonia aren’t struggling with their own sounds. Instead, they're affected by others typing, clicking pens, or, more often, chewing. The sound of someone snacking is routed from the cochlea, or cavity in the inner ear, and becomes an electric signal that winds up in the brain’s amygdala, which processes fear and pleasure. That's true for everyone, but in misophonics, it lands with a thud. They’ve likely developed a trigger, or negative association, with the sounds stemming from an incident in childhood.

“If you are scolded by a parent and they happen to be eating, or smacking, it becomes negative reinforcement,” Bauman says. Chewing, lip smacking, and even breathing become intolerable for sufferers, who often feel agitated and nervous, with corresponding increases in heart rate. Some fly into a rage.

Misophonics don’t necessarily recoil at all of these sounds all of the time: It may depend on who’s doing the snacking. Often, it’s a co-worker, spouse, or family member munching away that prompts a response. Fearing they’ll damage that relationship, sufferers tend to vent online. The misophonia subreddit is home to threads with titles like “And the popcorn eater sits RIGHT next to me on the plane” and “Chips can go f-ck themselves.” (The entire content of the latter: “F-ck chips, man. That is all.”)

Bauman says misophonia can be treated using cognitive therapy. An earpiece can provide white noise to reduce trigger sounds while sufferers try to retrain their brain to tolerate the noises. But even the sight of a bag of chips can be enough to send them scrambling.

People with misophonia might also want to exercise caution when traveling. Although some Asian cultures minimize crunchy snacks because loud snacking is considered impolite, other parts of the world can produce noisier mealtimes. “In parts of Asia, you show appreciation for food by slurping,” Spence says. Slurping is even associated with a more intense flavor experience, particularly when it’s in the setting of a comparatively quiet dining establishment.

Western culture favors noisier restaurants, and there’s a good reason for that. Supposedly Hard Rock Café has mastered the art of playing loud and fast music, resulting in patrons who talked less, ate faster, and left more quickly, allowing operators to turn over tables more times in an evening.

Spence believes sound will continue to be important to gastronomy, to chefs, and to food companies looking to sell consumers on a complete experience. Snack shelves are now full of air-puffed offerings like 3-D Doritos and Pop Chips that create pillows of taste. With less volume, you’ll snack more and crunch for longer periods.

A woman snacks on a chip

But the sound of the chip is just one part of the equation. The way a bag feels when you pick it up at the store, the aroma that wafts out when you first open the bag, the concentration of flavor from the granules of seasoning on your fingers—it’s all very carefully conducted to appeal to our preferences.

“When we hear the rattle of crisps, it may encourage people to start salivating, like Pavlov’s dogs,” Spence says, referring to the Russian scientist who trained his canines to salivate when he made a certain sound. We’re conditioned to anticipate the flavor and enjoyment of chips as soon as we pick up a package. Even hearing or saying the words crispy and crunchy can prime us for the experience.

When we’re deprived of that auditory cue, we can get annoyed. After news reports emerged that Pepsi CEO Indra Nooyi had mentioned her company might consider a quieter version of Doritos for women—an idea PepsiCo later denied they would label in a gender-specific fashion—women Doritos enthusiasts rallied around the Texas state capitol, condemning the perceived gender discrimination. To protest the possible dilution of their favorite snack, they made a spectacle of crunching Doritos as loudly as they could.

Your Bacon, Egg, and Cheese Sandwiches Have a Hefty Carbon Footprint

Most people know that eating meat, especially red meat—say, hamburgers—is bad for the environment. Raising enough methane-farting, resource-intensive cows to satisfy our cravings for burgers and steaks produces an outsized carbon footprint that plays a significant role in climate change. But what about your breakfast egg-and-cheese? A new study says you should feel guilty about that, too.

Recent findings reported in the journal Sustainable Production and Consumption examine the carbon footprint of 40 different kinds of sandwiches—from the simple ham and cheese to tuna, BLTs, and breakfast sandwiches—both homemade and pre-packaged. Researchers from the University of Manchester calculated the carbon necessary to produce standard recipes, including the agriculture required for the ingredients, the manufacturing of the packaging materials, the refrigeration required to keep the sandwiches cold, and the waste generated. They sourced their estimates from previous studies on the carbon footprint of producing and transporting ingredients like bread, ham, bacon, lettuce, tomato, and canned tuna as well as the energy cost of manufacturing packaging, transporting materials, and taking waste to the landfill.

They found that of all the sandwiches, those that combined pork (or prawns, because prawn and mayonnaise sandwiches are apparently a popular thing) and cheese are the most carbon-intensive. A bacon, egg, and cheese breakfast sandwich clocked in as the most environmentally taxing sandwich of them all, with a carbon footprint of 1441 grams CO2 equivalent—a measurement of the global warming potential—per sandwich. (The diet of the average meat-eater in the UK produces about 7200 grams CO2 equivalent daily. For comparison, if you drive your car four miles, it emits about 1650 grams CO2, roughly.)

Chicken and tuna sandwiches were slightly less carbon-intensive, but vegetarian sandwiches didn't fare as well as you might think—depending on how much and what type of cheese was involved, they could have carbon footprints as high as some of the meat sandwiches.

The researchers suggest that some improvements to the way sandwiches are produced and sold might decrease their carbon footprint by as much as 50 percent. Reducing the amount of meat, eggs, and cheese used, excluding tomato, lettuce, or mayo, reducing packaging, and other changes could all contribute to shrinking a sandwich's carbon footprint. Unfortunately, here's a limit to how much a sandwich's environmental impact can be reduced. You can't really have a BLT without the B, L, or T.

But if you're making it instead of buying it, you're saving a lot of emissions. As you might expect given the environmental cost of packaging, ready-made commercial sandwiches had a much bigger carbon footprint than their homemade counterparts containing the same ingredients—2.2 times larger, in fact.

Just another reason to feel guilty about not bringing your own lunch from home.


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