A new global analysis suggests that adolescents who eat more ultraprocessed foods are more likely to be overweight or obese. But while the pattern is consistent across studies, researchers say the relationship is more complex than it may first appear.
The study, a systematic review and meta-analysis of 23 observational studies involving about 155,000 adolescents published in PLOS One, found that higher intake of ultraprocessed foods was associated with a 63% increase in the odds of overweight or obesity. In some of the most recent studies, that difference was even larger.
Ultraprocessed foods are typically defined as industrial products made with refined ingredients, additives and formulations not commonly used in home cooking. That category can include a wide range of foods, from packaged snacks and sugary drinks to some ready-to-eat meals, making it a broad and sometimes debated classification.
Across the studies analyzed, the link between higher ultraprocessed food intake and weight outcomes appeared in multiple regions, including North America, Europe, Asia and Africa. That consistency strengthens the overall signal, even as individual studies varied in how they measured both diet and obesity.
Still, the findings do not establish that ultraprocessed foods directly cause weight gain. All of the included studies were observational, meaning they can identify patterns but cannot isolate cause and effect. Adolescents who consume more ultraprocessed foods may also differ in other ways that influence health, including physical activity, access to fresh foods and broader dietary habits.
That context is important because ultraprocessed food intake often reflects larger patterns in how people eat. Diets higher in these foods tend to be lower in fiber, fruits and vegetables and may be more calorie-dense overall. At the same time, not all ultraprocessed foods are nutritionally identical, and the category can include both lower- and higher-quality options.
The authors note that more recent studies showed stronger associations, which may reflect rising consumption levels or changes in food environments over time. But they also emphasize the need for more detailed research to better understand how different types of foods, eating patterns and lifestyle factors interact.
The findings add to a growing body of evidence linking ultraprocessed food consumption with a range of health outcomes. At the same time, they highlight an ongoing challenge in nutrition science: separating the effects of individual food categories from the broader context in which they are consumed.
The authors reported no specific funding and no competing interests.