Young people are more vulnerable to ultra-processed foods, according to a study

According to a new study, young people may be particularly vulnerable to ultra-processed foods and more likely to overeat when they consume a diet rich in them.

In a strictly controlled feeding trial from Virginia Tech, 18- to 21-year-olds ate more at an all-you-can-eat breakfast and again when offered snacks, even when they were not hungry, after two weeks on a diet rich in ultra-processed foods (UPF), compared to their slightly older Generation Z peers.

Researchers enrolled 27 adults ages 18 to 25 in a crossover study that compared two diets: one with 81 percent of calories from UPF and one without any. Each diet lasted two weeks, with meals prepared in a laboratory and combined in calories and nutrients. After each phase, participants ate freely from a large breakfast buffet, offering about 1,800 calories, and then participated in a snack test to measure whether they would continue eating even when they were not hungry.

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Younger adults ages 18 to 21 consumed nearly 100 extra calories and were more likely to eat when they were not hungry after the ultra-processed diet, according to the findings, which were published Nov. 19 in the journal Obesity.

“The young people ate about 90 more calories after the UPF diet, and if that occurred three times a day for three main meals, that would represent about 270 additional calories per day,” Brenda Davy, lead author of the paper and a professor in the Department of Human Nutrition, Food and Exercise at Virginia Tech, told Fox News Digital. “Over the course of a week, that could represent almost 2,000 additional weekly calories.”

“This type of eating habit, eating when you're not hungry, is linked to weight gain and an increased risk of obesity,” Davy added.

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The researchers said the pattern could occur in real life and have long-term implications. Campus cafeterias, takeout and food courts give young people unlimited access to ultra-processed products, often combined with sugary drinks and snacks.

The findings were not affected by participants' sex or body mass index (BMI), a measure of body fat.

Virginia Tech scientists Brenda Davy, left, and Alex DiFeliceantonio investigated the influence of ultra-processed foods on young adults. (Clayton Metz for Virginia Tech)

“I thought BMI would be the factor that mattered, but it was age,” said neuroscientist and co-author Alex DiFeliceantonio, an assistant professor at Virginia Tech's Fralin Biomedical Research Institute. “The younger you were when you entered the study, the more you ate after the UPF diet compared to the non-UPF diet,” he told Fox News Digital.

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The study, which was funded by a grant from the National Institutes of Health, was small and short in duration, so the results cannot show long-term weight changes or real-world eating patterns. The experiment also measured behavior in a single buffet meal and in a short snack test, which does not fully reflect how people eat during the day or on a college campus with constant access to food. “Future studies are needed to determine whether this occurs over the course of a day or a week,” Davy noted.

Researchers say larger, longer trials involving younger adolescents and real-life eating environments could help reveal how UPFs influence appetite and the brain's reward systems over time. “We need to understand what is in ultra-processed foods that could have these effects,” DiFeliceantonio added.

College-age participants (not pictured) in a Virginia Tech trial ate more calories after two weeks of eating an ultra-processed diet. (iStock)

The researchers based their work on the NOVA classification system, which classifies foods according to their degree of industrialization or alteration from their original form. In this framework, UPF includes soft drinks, packaged snacks, flavored yogurts and frozen meals made with additives and ingredients that are not usually found in home cooking.

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Some experts, however, reject the UPF definition, saying it is too broad.

“Health authorities around the world have rejected the use of the concept of 'ultra-processed foods' as a basis for public health policies, citing its lack of scientific consensus, its imprecision and potential to cause confusion, and the risk that it could undermine established, evidence-based nutritional strategies,” the International Food and Beverage Association previously told Fox News Digital.

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Dr. Evan Nadler, who co-directed the National Childhood Obesity Programs at National Children's Hospital in Washington, D.C., before founding ProCare Consultants and TeleHealth, said that while NOVA needs improvement, it is “the best we have for now.”

The study raises concerns about how highly processed foods affect young people's appetite and development. (iStock)

Nadler said the Virginia Tech findings fit with what is already known about adolescent development. “Teenagers are already prone to making rash decisions, and eating UPF may be another one,” he said, adding, “I suppose younger children might be even more susceptible to the effects of UPF.”

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Still, Nadler said, “this is excellent preliminary data for a larger study that I hope will include children under 18.”