If you eat a lot of processed food, a recent study should freak you out.
Researchers at Harvard’s T.H. Chan School of Public Health just published findings showing that U.S. adults who ate the highest amounts of ultraprocessed foods had a 58% higher risk of developing dementia later in life.
They also had a 46% higher risk of cognitive impairment, compared with people who ate the least.
The study was published in June in the American Journal of Public Health, alongside more than a dozen others that paint an ugly picture of what the modern American diet is doing to our brains, hearts and wallets.
Here’s what you need to know.
1. The numbers are new, and they’re scary
The Harvard team tracked older U.S. adults and compared the highest ultraprocessed-food eaters to the lowest. The high-consumption group’s dementia risk was 58% higher, and their cognitive impairment risk was 46% higher.
Senior author Cindy Leung at Harvard pointed out the flip side: People who ate the most minimally processed foods like whole grains, fruits and vegetables had lower risks of both cognitive impairment and dementia.
In other words, real food protects your brain. Engineered food hammers it.
It’s not the first time researchers have flagged this. A 2024 study linked even a 10% bump in ultraprocessed food intake to a 16% higher risk of cognitive impairment and stroke. The new numbers are just bigger.
2. We’re eating a stupid amount of this stuff
According to the U.S. Centers for Disease Control and Prevention, 53% of American adults get most of their daily calories from ultraprocessed foods. For kids ages 1 to 18, the number jumps to 62%.
And roughly 70% of the foods on U.S. grocery store shelves are highly processed. So trying to avoid them isn’t just a willpower problem — it’s a logistics problem.
3. Ultraprocessed means more than chips and soda
The category includes the obvious stuff: soda, packaged cookies, frozen pizza, hot dogs, sugary cereals, energy drinks.
But it also covers food that masquerades as healthy — flavored yogurts, plant-based meat substitutes, protein bars, store-bought bread, flavored nuts and many “natural” sauces and dressings.
If the ingredient list reads like a chemistry homework assignment — emulsifiers, hydrogenated fats, protein isolates, modified starches, artificial flavors — it’s almost certainly ultraprocessed.
4. The researchers think it’s no accident
A second study published the same day, co-authored by University of Michigan psychologist Ashley Gearhardt, argues that food companies engineer products with precise combinations of sugar, fat and additives to create something close to chemical addiction.
Gearhardt’s prior research found that more than 12% of older Americans, and 21% of women ages 50 to 64, are now clinically addicted to ultraprocessed food. Globally, 12% of children meet the same threshold.
That doesn’t sound like a willpower problem. That sounds like a product designed to override willpower.
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5. Americans of every political stripe are fed up
Another survey published the same day in the American Journal of Public Health found that 77% of Americans — Republicans, Democrats and Independents — want mandatory warning labels on ultraprocessed food packages.
Up to 70% want companies banned from advertising these products on children’s TV. And 87% want government safety testing for the laboratory-made chemicals that end up in our food.
That’s not a Republican issue or a Democrat issue. That’s a “have you read the back of a cereal box lately?” issue.
6. Don’t hold your breath for Washington
The food industry spends a fortune protecting the status quo. Between 1999 and 2020, ultraprocessed food companies spent roughly $1.15 billion on federal lobbying — more than the gambling, tobacco or alcohol industries spent.
The Make America Healthy Again commission promised decisive action on ultraprocessed food by August 2025. The final report, released in September 2025, mostly promised the government would keep working on a definition of the category. That’s not action. That’s a stall.
7. The fix is cheaper than you think
Here’s the part nobody in Washington wants to talk about: Eating less ultraprocessed food saves you money. Big money.
Whole oats are cheaper than name-brand sugary cereal. Dried beans are cheaper than canned chili. A roast chicken with rice and frozen vegetables is cheaper than a frozen entree. Tap water is cheaper than soda. Apples and carrots are cheaper than chips.
The food industry has spent decades convincing us that convenience is worth the markup. The new research suggests it isn’t — not for our brains and definitely not for our budgets.
If you want a starting point, our roundup of foods that might help fight off dementia is a decent place to begin.
The bottom line
I’m not telling you to throw out everything in your pantry. But the evidence is piling up fast, and it’s no longer easy to dismiss. A 58% jump in dementia risk is not a number you can shrug off.
If you’ve been ignoring this stuff, today’s a fine day to stop. Read the labels. Cook a little more. Save a little money. And give your brain a fighting chance for the back half of your life.
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