What we know about the health risks of ultra-processed foods
ARI SHAPIRO, HOST:
Kids in the U.S. are now getting two-thirds of their calories from ultra-processed foods. It's a trend that's been going up over the last two decades, and obesity rates among kids are climbing, too. As part of our series Living Better, NPR's Maria Godoy has been looking into the health concerns raised by this kind of diet and what parents can do about it. Maria, how surprising is it that two-thirds of what kids eat these days is ultra-processed?
MARIA GODOY, BYLINE: Well, it's surprising and it isn't because if you consider one recent study found that 73% of the U.S. food supply's ultra-processed, then it starts to seem almost inevitable that's what our kids are eating. And this really cuts across socioeconomic lines. Whatever their parents' income or education level, kids are eating this stuff a lot.
SHAPIRO: How do you define ultra-processed? What does that actually mean?
GODOY: So a lot of food is processed. So you think canned tuna or smoked meat, fruit in syrup, and that's actually not what we're talking about. Ultra-processed foods are the product of industrial food manufacturing, so they include ingredients like hydrogenated oils, emulsifiers, flavor enhancers. They make the food taste good and last longer. It's food that's cheap, convenient and everywhere, as I recently saw when I went shopping in your typical American grocery store with Allison Sylvetsky. She is a nutrition researcher at George Washington University. Her work focuses on obesity and diabetes in kids.
SHAPIRO: OK. Take us there. Let's listen to some of your reporting.
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AUTOMATED VOICE: $2.59.
GODOY: When we walk into the store, the fresh produce section is front and center.
Here we go.
But the bulk of the store is filled with row upon row of packaged foods.
ALLISON SYLVETSKY: As we go through the aisles of the store, a large proportion of the foods are - would be considered ultra-processed.
GODOY: Just pick up a product, and read the ingredient list. Hydrolyzed protein isolates, high fructose corn syrup, colorings, bulking agents, added sugars - these are all telltale signs of ultra-processed food. Sometimes they can appear in places you might not expect them, like a package of tortilla chips I spot on the shelf.
Sugar. Why would you add sugar to tortilla chips? Onion powder, vinegar powder, maltodextrin - what's maltodextrin?
SYLVETSKY: It is usually used as a bulking agent. It is a filler in a lot of things to help with the texture of foods, and - yeah. it's a bulking agent.
GODOY: Sylvetsky says that just because a food is ultra-processed doesn't necessarily mean it's unhealthy. But in general, ultra-processed foods tend to be high not just in calories but also sugar, fat and sodium, which helps make these foods irresistible.
They're so good. Yeah.
SYLVETSKY: They're designed to taste good, and that's why it's hard for people not to eat them.
GODOY: But a growing body of evidence has linked overconsumption of ultra-processed foods to poor health outcomes in adults. Dr. Fang Fang Zhang is a nutritional epidemiologist at Tufts University.
FANG FANG ZHANG: Data showed increased risk of hypertension, type 2 diabetes and obesity among adults and mortality from cardiovascular disease.
GODOY: In fact, she says, research has linked eating too much ultra-processed food to a higher risk of dying prematurely from all causes.
FANG FANG ZHANG: The evidence are pretty strong and consistent.
GODOY: But what's not clear is why. What is it about ultra-processed food that drives these poor health outcomes? Is it just because they are usually high in salt, sugar and fat? Or is it something about the processing itself? That is the question Kevin Hall wanted to answer. He studies obesity and diabetes at the National Institutes of Health.
KEVIN HALL: And so we decided to try to investigate this by designing two diets that were matched in terms of their salt, sugar, fat and fiber as well as overall carbs but in one case was coming 80% of calories from ultra-processed foods and, in the other case, 80% of calories from minimally processed foods and no ultra-processed foods.
GODOY: Twenty people spent a month living at NIH. They ate one diet for two weeks. Then they switched to the other. They were allowed to eat as much as they wanted. The results surprised Hall.
HALL: I had sort of expected, because the diets were matched for all these nutrients of concern, there wouldn't be any difference. People would basically eat the same number of calories, basically maintain their usual weight.
GODOY: But in fact, people on the ultra-processed diet ate 500 calories more per day on average, and they gained weight. When they switched to the unprocessed diet...
HALL: They basically just spontaneously lost weight and lost body fat.
GODOY: The findings were considered landmark. They strongly suggest it's not just the salt, sugar and fat but something about the highly processed nature of the food itself that propels people to overeat. Researchers still aren't sure exactly what is going on, but many agree there's something there. Now, when it comes to kids, the evidence is more limited, but childhood dietary habits often carry over into adulthood. So experts say cutting back on how much ultra-processed foods kids are eating now can help set them up for better health over the long haul.
SHAPIRO: Maria, if ultra-processed food is everywhere and tempting to snack on, what can parents or anybody who wants to cut back on ultra-processed food do?
GODOY: The most important thing is to learn how to recognize it, and that means reading the ingredient list. If there are ingredients that you really, truly don't recognize, that's a sign it's ultra-processed. And sometimes you just have to compare packages. So if you're buying tortillas, one might have corn, lime and salt, and the other one might have a whole list of emulsifiers and stabilizers. Personally, I go for the corn, lime and salt. Researchers at Northeastern actually created a pretty nifty database called truefood.tech that lets you browse for food items to see how processed they are. And it even suggests less-processed alternatives.
SHAPIRO: What if ultra-processed foods are the only options? Some people don't have easy access to stores with lots of fresh ingredients, or fresh foods can be more expensive.
GODOY: Right. Well, you can make healthier choices even in the ultra-processed category. So, for instance, if you're buying packaged bread, go for whole grain. It's high in fiber and lower in sugar, and that's going to be better than white. Or, with breakfast cereals - again, look for low sugar, high fiber and high protein 'cause that still matters. Or, you know, if you buy canned beans and they're high in sodium, rinse them off with tap water to flush out the extra salt. And if you have really young kids, you can actually head some of this off from the get-go by trying to get them used to tastes that aren't so sweet because a lot of packaged food aimed at kids is super-sweet. And that's kind of how they get you.
SHAPIRO: So you're saying it might not be necessary to completely eliminate ultra-processed food from our diets altogether.
GODOY: I don't think that's realistic for most people. I would say try to focus more on what you should be eating, fruits and vegetables - fresh or frozen because frozen is often cheaper, and it is just as nutritious and lasts longer. But you really don't have to be perfect all the time. In fact, one of the best bits of advice I heard was from Christopher Gardner. He's a nutrition researcher at Stanford University, and he says he likes to follow a rule his favorite chef coined - like, the 80-20 rule.
CHRISTOPHER GARDNER: She chooses very intentionally 80% of the time, and 20% of the time, she has fun with food because food brings us joy. And she goes off the rails, if she wants, for that 20% 'cause 80% of the time, she eats really well.
GODOY: So you do want to aim for a better balance between ultra-processed and minimally or unprocessed food. But to start, maybe just focus on a few small changes because that can add up over time.
SHAPIRO: NPR's Maria Godoy. Thank you.
GODOY: Thanks, Ari.
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