Ultra-Processed Foods Linked to Increased Calorie Intake and Snacking in Young Adults
A new study reveals that a diet high in ultra-processed foods can lead to excessive calorie consumption, even when individuals aren’t hungry, particularly among those aged 18 to 21. The research, published Wednesday in the journal Obesity, highlights a concerning link between readily available, highly palatable foods and potential weight gain in young people.
Currently, ultra-processed foods account for as much as 65% of the daily caloric intake for Americans between the ages of 15 and 24, raising significant public health concerns. These foods, characterized by ingredients extracted from whole foods – such as saturated fats, starches, and added sugars – along with numerous additives, are designed for taste, convenience, and extended shelf life. Common examples include packaged baked goods, sugary cereals, ready-to-eat meals, and processed deli meats.
Researchers at the Fralin Biomedical Research Institute at Virginia Tech sought to understand if exposure to these foods could directly spur overeating. To investigate, a team led by Alex DiFeliceantonio conducted a study involving 27 participants, aged 18 to 25. For two weeks, participants followed one of two carefully controlled diets: one consisting of 81% ultra-processed foods, and another completely free of them. Notably, the diets were meticulously matched in terms of macronutrient and micronutrient profiles to reflect a typical U.S. diet.
“We very rigorously designed these diets to be matched on 22 characteristics, including macronutrients, fiber, added sugar, energy density and also many vitamins and minerals,” explained Brenda Davy, the study’s senior author and a professor of human nutrition, foods and exercise at Virginia Tech. “Previous studies had not matched diets to this extent.”
Following the two-week dietary intervention, researchers tracked participants’ eating habits over a month of “normal” eating, paying close attention to consumption at an “all you can eat” breakfast buffet and subsequent snack choices. While the overall group showed no significant change in calorie intake or preference for ultra-processed foods after the intervention, a distinct pattern emerged when the data was analyzed by age.
The younger participants – those between 18 and 21 years old – consumed significantly more calories at the breakfast buffet after completing the diet high in ultra-processed foods. Crucially, they also exhibited a marked increase in snacking, even after having already eaten breakfast and reporting they weren’t hungry.
“Given the opportunity to snack when not hungry, they ate more yet again,” noted DiFeliceantonio, an assistant professor in the Department of Human Nutrition, Foods, and Exercise. This tendency was not observed in the older participants or those who had followed the diet emphasizing unprocessed or minimally processed foods like fruits, vegetables, and whole grains.
Researchers caution that while this was a short-term trial, the observed increase in caloric intake could contribute to weight gain over time. “Although this was short-term trial, if this increase in caloric intake persists over time, this could lead to weight gain in these young people,” Davy stated.
The team emphasizes the need for further research, particularly with larger groups of younger adolescents and in more realistic settings. Future studies should also explore the underlying mechanisms – potentially involving brain activity and specific biomarkers – that explain how certain foods might trigger overeating.
For more information on ultra-processed foods, visit the Johns Hopkins Bloomberg School of Public Health.
