Remember that catchy Pringles jingle "Once you pop, the fun don't stop?" Before that, processed food giant Kellogg's used a more direct version to sell its salty, manufactured potato "crisps," and it was much more accurate. The old slogan was, "Once you pop, you can't stop."
Many people have experienced that phenomenon with a variety of foods — from McDonald's chicken nuggets to Oreos — and despite what diet sellers will try to tell you, it's not a lack of willpower that drives it. "Once you fall hard for [processed foods], your entire body works against any efforts on your part to regain control," says Michael Moss. "And companies have changed food so dramatically that our biology hasn't had time to catch up. Maybe 500 years from now we'll have some genetic changes that will allow us to recognize that we're overeating junk food, but we don't have that now."
In his new book, "Hooked: Food, Free Will, and How the Food Giants Exploit Our Addictions", Moss digs deep into what research and expertise on evolutionary biology, brain chemistry and addiction can tell us about how and what we eat and how food companies use that science to formulate flavors and foods we can't resist.
The book sheds new light on the role that "ultra-processed foods" play in contributing to the modern health crises like obesity and diabetes that are now a fixture of American life. And it provides clues as to the kinds of interventions that might enable people to adopt healthier habits that help them to resist the allure of cheap calories and make healthier choices in the future.
Are processed foods unhealthy?
For a long time, the dominant understanding of what makes a food healthy or unhealthy has come from a paradigm called "nutritionism." Essentially, this way of thinking assumes a set of numbers that calculate metrics like calories, macronutrients (protein, carbs, and fat), and micronutrients (vitamins and minerals) provides an understanding of how nutritious any given food is.
Historically, food companies have leaned into this paradigm. Moss writes about a 1969 White House panel at which a VP of Monsanto (one of the world's biggest food, agriculture and chemical companies, now owned by Bayer) suggested the idea of putting nutrition facts on packaging. Companies assumed, he says, that the mere presence of the information would ease concerns about what was in the package. "The majority of people don't even look at that information and those who do are rather perplexed by it, except for one basic reaction, which is, 'It's a lot of data from the government. It must mean that this product has been studied and certified as being okay!'" he says. "That's where the industry was coming from."
But most of what research shows is wrong with processed foods won't show up on a label. Individual hard-to-pronounce additives get lots of attention for being either dangerous or perfectly safe depending on who you talk to, but it's the complicated sum of what's being delivered that matters.
Past studies have looked at associations between eating processed foods and negative health outcomes. They've found that higher intake of processed foods is correlated to higher risks of cancer, heart disease, and death. But these kinds of studies do not show causality, and confounding factors can't be ruled out.
Past studies have looked at associations between eating processed foods and negative health outcomes. They've found that higher intake of processed foods is correlated to higher risks of cancer, heart disease, and death. But these kinds of studies do not show causality, and confounding factors can't be ruled out.
However, in 2019, researchers at the National Institutes of Health published the results from a clinical trial they designed to determine whether or not something about processed foods in particular — not just overeating in general — was leading to negative health outcomes. Experts in the field called the results striking, even with the study's small sample size.
The researchers had 20 healthy adults live in a controlled environment for four weeks, where all of their meals were provided and every bite and health metric could be accounted for. Participants were split into groups on unprocessed (whole foods) or processed food diets, and they were presented with meals that were identical in terms of nutrition facts. While the meals put in front of them contained the exact same calories, macronutrients, sugar, salt, and fiber, participants ate significantly more when the food was processed and gained significant weight. On the ultra-processed diet, participants also had higher levels of a hormone that stokes hunger and lower levels of a hormone that signals fullness. Finally, they ate faster.
Why can't we stop eating ultra-processed foods?
Speed is one of the factors Moss says led him to conclude that processed foods can be more addictive than drugs, depending on the individual. "Speed is a hallmark of addictive substances. And it turns out there's nothing faster than food in the way that it hits the brain," he says.
While it can take 10 seconds for a drag on a cigarette to fully engage the brain, experiments show sugar can register in less than a second. Processed foods ignite our desire quickly and then get into our stomach rapidly — their processed nature means we don't have to cut or chew nearly as much. And those bites are usually more energy dense — they contain more calories per gram — so they deliver more food quickly. Think about how long it would take you to eat a whole apple compared to one of those snack-size bags of Doritos. The apple has 95 calories while that handful of chips has 140. "By the time the gut sends the signal for us to stop, it's way too late," Moss writes.
Then you layer on the other fascinating but frustrating parts of our biology that are designed for running down antelope and foraging for fruits, not strolling past packed shelves at Costco. Experiments show our bodies are designed to crave calories in any form, and evolutionary biologists say that's because we needed to find as many as possible to survive. "We have sensors in the gut and possibly even in the mouth that detect calories when we're eating or drinking, and the brain gets excited by calories almost as much as it gets excited about sugar. [Our ancestors] wanted more calories…because that meant our brains could grow and we could have more offspring and we could get through hard times," Moss explains. "So what do companies do with that? They create snack foods with nutrient-empty calories densely packed in a way that gets the brain really excited and kind of overwhelms our ability to put the brake on overeating."
Our brains also get excited by variety because we need a wide range of nutrients for good health, hence ever-changing new flavors and variety packs of cookies, chips, and cereals. And our bodies hold onto body fat because our hunter-gatherer ancestors needed it to get them through times when food was hard to find. "I knew that fat cells never went away. They just kind of shrivel up if you lose weight and then lay in wait for when you have another feast," he says. "But I had no idea that body fat works to preserve itself by telling the brain that you're hungry when you're not and or even sort of slowing down your resting metabolism."
Finally, Moss found that memory plays a huge role. Every time you eat, especially as a child, tracks are laid in your brain that connect the food we're eating to memories. If you eat the same foods repeatedly, those tracks get deeper and deeper and impact your desire (or lack of desire) for certain foods, especially when exposed to a cue. Imagine a McDonald's billboard as a cue, for example. "If you've eaten there before, and have deep channels carved in your brain by Big Macs, French fries, and milkshakes past, the sign will stir up the memory of those meals, which in turn might sweep you toward the restaurant in a flood of desire. But for someone else, who seldom eats at McDonald's and thus lacks those channels, it will be like the sign isn't even there," he writes.
In today's world, is it possible to skip ultra-processed foods?
The role of memory points towards an important point: To reduce addiction to and the overeating of processed foods, preventing those memories from being etched in the brains of children may be one of the most effective interventions. All of the other factors would remain, but at least kids would have a leg up. Moss said that his wife jokes that you have to feed kids broccoli 19 times and then the 20th time they'll like it. While those numbers are random, multiple studies have shown having young children repeatedly taste vegetables can increase how much they like them.
To that end, Dan Giusti might have some of the answers. Giusti is the chef-founder of Brigaid and one of the founding directors of ScratchWorks, a new organization that brings together individuals and organizations who have been working for years to get more scratch cooking into schools all over the country.
Giusti is not driven specifically by a desire to keep kids away from processed foods, but his approach might achieve that aim regardless. "If you look at school food, it's tackling two main things. It's making sure kids are fed and then giving them proper nutrition," he says. "With the nutrition piece, scratch cooking is paramount in the sense that you know exactly what you're putting in your food. Otherwise, if you're buying all processed foods, you're just adding tons and tons of ingredients and there's really no way to control that."
And in the schools Brigaid has been cooking in for the past several years, Giusti has seen students forming healthy food memories over and over. "Kids are getting exposed to things that they otherwise wouldn't have gotten exposed to, like a fresh prepared vegetable that maybe they wouldn't have eaten at home that now they've eaten and they enjoy it, and that's all it takes," he says. "I'm a firm believer that if something tastes good, it doesn't matter what it is. If it tastes good to the kids, then it's a big win and they're gonna want to eat it wherever they are."
But what about other eaters who already have fully formed memories of Pop-Tarts and Burger King and have to contend with biological factors beyond their control?
While home cooking is an obvious solution, it's often not a possible or equitable one in today's modern world, where many families are struggling to get dinner on the table while juggling multiple jobs, childcare, and tight budgets. But now that Giusti is skilled at getting healthy, fresh meals to kids quickly, for just a few dollars a serving, in often ill-equipped kitchens, he's more confident that more adults could make healthy, affordable meals for themselves more often.
"Cooking in schools is already challenging, but getting more engaged in terms of helping parents and giving parents the resources to find ways to cook at home, that's something that I'm passionate about," he says. "For example, how can you make a meal at home…within the same vein of how we approach school food, needing minimal equipment, not needing a crazy skill set, not needing too much time, and of course being cost-effective, even from a shopping perspective?" Giusti has started making videos in which he teaches home cooks to do just that; the first one features him using frozen foods to make four fast dishes that come in at under $3 per serving.
Moss, for his part, says he's gotten his homemade spaghetti sauce recipe down to 93 seconds, and he frames this kind of convenient, fast cooking as "taking back what [food companies] took from us." And he's optimistic that more people will be able to do that armed with information on their own biology and how companies exploit it, even given how complex the problem is.
"Eating good, healthy food eventually can cause us to like and want more of that. The only problem is it takes time," he says. "So if you have a lifetime of bad eating habits built up and the memories from that are dug deeply into your brain, you can't expect to erase it and start over within a matter of days or weeks. It takes a long time…but convenience has been oversold to us by the processed food industry."
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