In a government hospital in Bethesda, Maryland, 20-year-old Florida college student Sam Srisatta spent an unusual autumn—not due to illness, but as a volunteer in a scientific nutrition study. For 28 days, his entire routine was controlled by researchers: every bite of food he ate was recorded, and every aspect of his daily life, from meals to physical activity, was tracked with precision.
“My lunch today? Chicken nuggets, some chips, and ketchup,” Srisatta said with a grin as he played video games in the research unit. He was one of more than 30 participants who received $5,000 each to dedicate nearly a month of their lives to science.
The study, led by Dr. Kevin Hall, a nutrition researcher at the National Institutes of Health (NIH), aims to better understand the health effects of ultraprocessed foods—those industrially manufactured products packed with additives and artificial ingredients. In the U.S., these foods now make up over 70% of what the average person eats.
The big question? Why do we love these foods so much—and what exactly are they doing to our bodies?
Hall explained, “Our goal is to figure out the underlying mechanisms—what exactly is it that makes these foods so appealing and, at the same time, potentially harmful?”
This isn't Hall’s first foray into ultraprocessed food research. In a previous trial, he found that even when two groups consumed the same number of calories—one group eating minimally processed foods, the other ultraprocessed—the latter gained more weight and ate faster. That suggested that something beyond calories and nutrients was influencing people’s behavior.
Now, the research is going deeper. Volunteers like Srisatta were fed three daily meals within a tightly controlled lab environment. On the menu: heavily processed meals like frozen chicken nuggets, jarred spaghetti sauces, and factory-made snacks. Participants couldn’t change their meals or snacks—every portion was fixed and measured. Meanwhile, the scientists monitored blood sugar, hormone levels, gut bacteria, and more.
Why does this matter? Because the average American is constantly surrounded by these foods: boxed cereals at breakfast, a bag of chips with lunch, a microwavable pizza for dinner. These items are convenient, cheap, and engineered for pleasure—but they may be quietly harming our health.
Take Emily Thomson, a young graphic designer from the U.K. Her daily lunch used to be a packaged sandwich, some chips, and a can of energy drink—seemingly harmless, even marketed as “low fat” or “high protein.” But within six months, she gained nearly 15 pounds and began experiencing insomnia. At her doctor’s advice, she started cooking simple meals from fresh ingredients—grilled chicken with roasted vegetables, for example. Within weeks, she felt more energetic and slept better.
“I didn’t even realize how sluggish I’d become until I stopped eating that stuff,” she recalled. “Once I did, my body just started working properly again.”
What researchers like Hall are uncovering is that ultraprocessed foods may affect us far beyond what nutrition labels show. These foods are often low in fiber and protein, making it harder to feel full. They're also engineered to be hyper-palatable—just the right combo of salty, sweet, and crunchy—to trigger dopamine in the brain, making us crave more.
“It’s almost like we’re being programmed,” Hall said. “Once you start eating, it’s incredibly hard to stop.”
There’s also growing evidence that diets high in ultraprocessed foods are linked to obesity, diabetes, heart disease, and other chronic conditions. And it’s not just a U.S. problem. Countries like the U.K., France, and Australia are seeing similar spikes in consumption and associated health issues.
Completely eliminating ultraprocessed food in modern life is probably unrealistic. These foods are fast, cheap, and designed for our busy schedules. For office workers, students, or people living alone, they’re often the easiest choice.
Still, experts suggest that awareness and moderation can go a long way. Preparing basic meals at home when possible, checking ingredient lists, and choosing less processed alternatives can all help. Even small changes—like swapping out packaged snacks for fruits and nuts—can make a noticeable difference over time.
The study is still ongoing, and Hall hopes it will eventually lead to more concrete guidelines—or even healthier processed foods that are just as convenient but less harmful.
As for Srisatta, his biggest takeaway after 28 days in the lab? “Processed food is definitely fun at first, but after a while, it just makes you feel… off,” he said.
Sometimes, a real human reaction says more than any data chart ever could.