The Mysterious Pull of the Perfect Crunch
Have you ever opened a bag of chips with the intention of eating just a few, only to find yourself staring at an empty package thirty minutes later? The distinctive crack of that first bite was no accident. Food companies 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). This precise engineering creates what researchers call a “vanishing caloric density” – 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. It’s like your snack is playing hide and seek with your brain’s fullness signals.
Your Brain on Dopamine Overload
Junk food stimulates the reward system in the brain in the same way as addictive drugs, such as cocaine. For susceptible people, eating junk food can lead to full-blown addiction, which shares the same biological basis as drug addiction. Eating junk food causes a release of dopamine in the brain. This reward encourages susceptible individuals to eat more unhealthy foods. Think of dopamine as your brain’s personal cheerleader, shouting “Yes!” every time you bite into something delicious. The problem? When a person repeatedly does something that releases dopamine in the reward system, such as smoking a cigarette or eating a Snickers bar, dopamine receptors can start to downregulate. When there are fewer receptors, more dopamine is needed to reach the same effect, which causes people to start eating more junk food to reach the same level of reward as before. Your brain essentially becomes a snack food addict, constantly chasing that first high.
The Sound Science Behind Our Craving
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. In one experiment, researchers played crunching sounds at various volumes while their subjects ate potato chips. People who heard muffled crunches described chips as stale and soft, while loud crunching sounds were described as crispy and fresh. The sound literally becomes part of the taste experience – your ears are dining right alongside your mouth.
Evolutionary Tricks Gone Wrong
Evolutionary biologists have proposed that when our ancestors were foraging for food, crispness was a signal something was ready to eat and importantly, not yet spoiled. “We’re designed to find carbohydrates and fats reinforcing,” says Ashley Gearhardt. She’s a psychologist at the University of Michigan in Ann Arbor. Evolving such tastes helped our ancestors “outwit famine and make sure we survive,” she explains. That critical role shaped the brain’s reward system, making us hard-wired to enjoy carbs and fatty foods. Unfortunately, what helped cavemen survive winter is now making us reach for that third bag of cheese puffs on a Tuesday afternoon. Our Stone Age brains haven’t caught up to our 21st-century grocery stores.
The Perfect Storm of Fat and Sugar
“Sugar and fat don’t come together in nature,” Gearhardt says. But highly processed foods often “have unnaturally high levels of both carbohydrates and fat.” When we eat these foods, we get a quick “hit” of carbs and fats that give the brain a boost. When it comes to ultraprocessed snacks, sugar often goes together with fat—a combination that could make such foods even more addictive. A 2018 study by DiFeliceantonio and her colleagues showed that, compared with equally caloric foods containing only fat or only a carbohydrate, those made with both ingredients are far more efficient at activating the striatum, a part of the brain’s reward center that is implicated in addictions. It’s like hitting the jackpot on a slot machine, but the coins are dopamine and the machine is your brain.
The Mouthfeel Manipulation
The oral sensory experience of what we eat matters as well. We like the way foods, certain textured foods like cheese puffs feel as they break down in our mouths. Additives may also be contributing to the addictiveness of UPFs. Many UPFs have flavour additives that increase sweet and savoury tastes, as well as texturisers that improve the mouthfeel. Additives that aim to improve flavour and mouthfeel are also common in cigarettes, including sugar, cocoa, menthol, and alkaline salt. Including vanilla in a product, for example, can increase the perception of creaminess, even if there’s no cream in it. This is why food producers often add vanilla alongside another flavour to increase the indulgent experience of eating it, combining vanilla with strawberry in strawberry yoghurt, for example. Food scientists are basically magicians, making your mouth believe things that aren’t really there.
The Forty-Thousand-Dollar Crunch Research
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). Companies literally invested tens of thousands of dollars to figure out exactly how your teeth should feel when they bite down on their products. “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”. Your brain has been trained to expect specific sounds and sensations, and food companies are more than happy to deliver exactly what you’re looking for, over and over again.
When Reward Systems Go Haywire
The culprit behind bingeing and emotional eating is known as reward deficiency syndrome (RDS)—a disbalance between the brain’s reward system and dopamine, the “feel-good” hormone. The human brain is wired to repeat life-sustaining actions by associating them with sensations of pleasure or reward. This is exactly what happens when we eat appetizing food—our brain rewards us with a hit of dopamine. Studies have linked obesity and a higher BMI to weaker dopamine release in the brain, especially in the dorsal striatum area. The dorsal striatum, the area associated with reward and motivation, shows a greater response to food cues than to the actual act of eating itself in obese people. It’s like being excited about opening Christmas presents but feeling disappointed once you actually unwrap them – except the presents are snacks and your brain keeps demanding more wrapping paper.
The Marketing Machine Behind Your Munchies
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. “They’re clearly targeting 8- to 14-year-olds very aggressively to try and make them lifelong users,” Gearhardt says. That’s exactly what tobacco companies used to do. Perhaps it’s no surprise, then, that big tobacco companies now own many of the brands that make the most popular snack foods. The same people who got America hooked on cigarettes are now getting us hooked on Doritos.
Your Body’s Betrayal System
When we crave junk foods, along with the anticipatory release of dopamine in the brain, our stomach is producing ghrelin, known as the hunger hormone, which makes us seek out that calorie-dense junk food. And after we satisfy our craving, dopamine is released again, which creates this positive reinforcement loop. Another neurochemical in action is the hormone leptin, which signals our body that we should stop eating. But ultra-processed foods can interfere with the signaling, especially if people consume ultra-processed foods all the time because the hormone simply stops working. Your body’s natural “stop eating” button essentially gets jammed, leaving you at the mercy of that bag of chips.
The Laboratory-Designed Flavor Trap
One reason: they contain super-processed ingredients that give the brain a quick burst of fat and carbs. They also contain flavors we can’t make in our kitchens. “I don’t know how to make a Flamin’ Hot Cheeto or Vanilla Dr. Pepper,” Gearhardt says. But we start to crave those specific flavors. “You don’t just want the sugar and fat bits, you want the flaming hot burn.” These aren’t foods in the traditional sense – they’re engineered products designed to bypass your brain’s natural satisfaction signals. Companies add extra sweeteners and flavors “to increase the appeal of something which is, in fact, not that tasty, nutritious or healthy.” Those highly processed extras “won’t help you grow or make you stronger or better at sports,” he says. “If you tried [the foods] before they used all of those tricks, you would probably not like them.”
The Tolerance Trap
The more often this cycle of craving and rewarding is repeated, the stronger it becomes and the greater the quantity of food that’s needed each time. While four scoops of ice cream were enough 3 years ago, today it may take eight scoops to experience the same level of reward. This is called tolerance. If there are fewer dopamine receptors, the person will have very little dopamine activity and start to feel unhappy when they don’t get a junk food “fix.” This is called withdrawal. You literally need more and more of your favorite snack to feel the same satisfaction, just like any other addiction. Your brain has been hijacked, and the hijacker is asking for increasingly higher ransoms.
Fighting Back Against Food Engineering
One of the first steps is eat the orange instead of the store-bought orange juice, which has the fiber removed and often sugars added to it. When you eat whole food, you’re increasing fiber in your diet, which is not only filling, but it also reduces and lowers your cravings. Another easy step is making sure that you’re adequately hydrated. The hunger and thirst centers often get confused in the brain. I often say to people that when they’re craving junk food, they should drink a glass of water. Sometimes your brain thinks it wants Pringles when it actually just wants water – it’s like your body’s version of autocorrect gone wrong. Pay attention to what you eat, Gearhardt says. “The goal is not perfection.” It’s best to get plenty of nutritious foods for your mind and body. That doesn’t mean you can’t have a donut or pizza now and then. Just be sure you’re aware of what you’re eating.
The next time you hear that satisfying crunch, remember: you’re not just eating a snack, you’re participating in a carefully orchestrated symphony of science, psychology, and corporate engineering. Your brain thinks it’s getting a reward, but really, it’s just getting played. Pretty wild how a simple potato chip can outsmart millions of years of evolution, isn’t it?
