Eating More Ultra-Processed Foods May Increase Risk of Adolescent Obesity

Teenagers who eat more ultra-processed foods have a significantly higher risk of being overweight or obese, according to a new analysis by researchers at the University of Gondar, Ethiopia.

The analysis, published in PLOS One, reviewed data from 23 studies covering more than 155,000 adolescents across 16 countries. They found that adolescents with a higher intake of ultra-processed foods had 63% greater odds for overweight or obesity compared to their peers with lower intakes.

“Higher consumption of ultra-processed foods is linked to a substantially increased risk of overweight and obesity among adolescents, emphasizing the need for early dietary interventions,” the authors stated in a press release. “Improving adolescent nutrition today is essential to protecting long-term population health and reducing healthcare costs associated with obesity-related conditions.”

Ultra-processed foods linked to teen obesity

Being overweight or obese during adolescence can have serious health consequences for a person’s future. To date, studies have linked teenage obesity to an increased likelihood of developing type 2 diabetes, high blood pressure, kidney function abnormalities, asthma, sleep apnea, and polycystic ovary syndrome in adulthood.

With the rise in the availability of ultra-processed foods over the past several decades, researchers are keen to understand the potential impacts of diets high in ultra-processed foods on people of all ages.

In this latest study, researchers conducted a systematic review and meta-analysis of studies investigating ultra-processed food consumption and weight outcomes in adolescents aged between 10–19 years. This review identified 23 eligible studies, including one large Chinese study with more than 97,000 adolescent participants. The smallest study considered in the review involved just 76 adolescents.

In a meta-analysis covering all 23 studies, the researchers found that the teens who consumed high amounts of ultra-processed food in their diet had 63% greater odds of being overweight or obese compared to their peers. This association held across all of the different geographic regions included in the analysis.

A subgroup analysis of only the most recent studies—those published in either 2024 or 2025—showed the largest odds ratio (2.09). The researchers suggest that this may indicate that the association is growing as ultra-processed food consumption rises.

Is ultra-processing really the culprit?

The research authors do note several important limitations in their work. Not all of the studies included in the analysis used the same design; most were cross-sectional studies, but a handful used case-control methods, and one used a combined follow-up and cross-sectional approach. The studies were also all observational studies and so cannot suggest a causal relationship between ultra-processed food intake and obesity risk—despite the statistically strong association.

“We have to be careful though how we interpret this information as association is not causation, and we know that high consumption of ultra-processed foods [UPFs] is also associated with other behaviors and environmental factors that might be driving this association, particularly as UPFs tend to be cheap, convenience foods consumed by people living on a tight budget and time poor in terms of cooking,” Prof. Jules Griffin, director of the Rowett Institute at the University of Aberdeen, told the Science Media Centre.

This sentiment is echoed by Prof. Gunter Kuhnle, a professor of nutrition and food science at the University of Reading, who told the Science Media Centre: “A recent randomised controlled trial, conducted by UCL, has shown that it is possible to lose weight on a high UPF diet by following the UK’s dietary recommendations. This suggests that the associations between UPF intake and obesity—as described in this study—are more due to food composition and less due to processing.”

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“Focusing on the processing state of food instead is misleading and might have unintended consequences: many foods classed as “ultra-processed” have an overall beneficial nutrient composition (e.g., many breads contain wholegrain and fibre) while foods not classed as “ultra-processed” can be high in salt (e.g., artisan bread), fat or sugar (e.g., home made cakes),” Kuhnle pointed out.

While the large number of individuals included in the analysis does provide strength to this study, the heterogeneity between the individual studies included is a point of weakness, as the authors themselves point out. One thing that did unify the studies was their use of the NOVA classification to define exactly what foods are classified as being highly processed.

The NOVA classification groups food into 4 classifications: unprocessed or minimally processed foods, processed culinary ingredients, processed foods, and ultra-processed foods. The NOVA classification is the most common definition for ultra-processed foods used in scientific literature; however, it is not without critique. Some academics have criticised the classification for potentially fuelling negative perceptions towards all industrialized foods, which includes fortified foods that provide real health, economic, and social benefits in deprived areas.

“All the studies included used the NOVA classification, which has acknowledged limitations as it focuses only on the nature of processing without consideration of the nutritional value of the food and drink products,” said Dr. Hilda Mulrooney, reader in nutrition and health at London Metropolitan University, also to the Science Media Centre. “For me, this paper is a good illustration of the problem with the UPF classification and the difficulty of separating out a possible effect of processing from a definite effect of nutritional content.”

Reference: Aweke MN, Abuhay HW, Limenih MA, et al. Ultra-processed food consumption and the risk of overweight and obesity in adolescents: A systematic review and meta-analysis. PLOS One. 2026;21(4):e0344873. doi: 10.1371/journal.pone.0344873