April 15, 2026

expert reaction to study on the association between UPF consumption and overweight or obesity in adolescents

A systematic review published in PLOS One looks at an association between ultra-processed food (UPF) consumption and overweight or obesity in adolescents. 

Prof Jules Griffin, Director of the Rowett Institute, The Rowett Institute, University of Aberdeen, said:

“The manuscript by Aweke and colleagues is a global analysis of dietary studies that examine ultra-processed food consumption in adolescents and how this is associated with the risk of developing obesity. This analysis has brought together 23 different studies from all across the world, surveying 155,000 adolescents, and despite the very different study designs that were used in the individual studies, together they demonstrate a statistically strong association between increased consumption of ultra-processed foods and the risk of being classed as overweight or obese.

“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 is also associated with other behaviours 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.

“Because of the very different studies included in this analysis, the authors could not investigate what components of the diet might contribute the most to the associations – we know that ultra-processed foods are high in saturated fat, free sugar and salt, and low in fibre and micronutrients all of which could contribute to the association found.

“This study further strengthens the case for more research, such as randomised controlled trials, to examine the components of ultra-processed foods to understand why the association between ultra-processed food consumption and being classed as being overweight or obese arises in adolescent populations.”

Dr Amanda Avery, Associate Professor in Nutrition and Dietetics, University of Nottingham, said:

“The included studies are diverse in terms of which foods/drinks are considered as ultra-processed foods – some focus on fast food consumption, others just sweetened beverages and then others include a range of high fat, high sugar energy dense/nutrient-poor foods.

“Without looking at each of the 23 included studies, it is hard to determine what the individual research groups have defined as high or low consumption – or even what constitutes ‘safe’ consumption levels given that UPFs are so readily available.

“However, the comprehensive review confirms that there is an association between higher intakes of UPFs and an increased risk of excess weight in adolescents. It is important that this age-group have been identified as being especially nutritionally vulnerable given overweight and obesity during early life does increase the risk of premature morbidity and mortality.  Public health measures, such as the implementation of new school meal standards in England, are required to reduce the availability of nutrient poor UPFs and thus the consumption. Reducing the consumption of sweetened beverages, including energy drinks, is a ‘quick win’.”

Prof Gunter Kuhnle, Professor of Nutrition and Food Science, University of Reading, said:

“There has been a lot of discussion regarding the effect of ultra-processed food intake and obesity. The majority of data is from observational studies, such as those used in this review. While these studies are plentiful, they have several considerable limitations: first of all, they are unable to establish a causal link. Furthermore, they rely on dietary assessment methods that were often neither designed nor validated to estimate ultra-processed food intake and therefore rely on unreliable data. Finally, there is a high risk of residual confounding, especially as high consumers of so-called UPF often have otherwise unhealthy lifestyles.

“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 ^[1]. 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.

“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).”

References:

[1] https://www.nature.com/articles/s41591-025-03842-0

Dr Hilda Mulrooney, Reader in Nutrition & Health, London Metropolitan University, said:

“It is an interesting paper. Its strengths lie in the large numbers of individuals included (155,000 adolescents from 23 studies) and the well-described and well-defined protocols used. It found a significant positive association between consumption of ultra processed food (UPF) and overweight/obesity in adolescents. However, there was very high heterogeneity between the studies included in the review and as the authors themselves acknowledge, causality cannot be demonstrated from this sort of work – the observed positive association does not mean that overweight/obesity was caused by UPF consumption.

“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. It is not possible to say that the observed positive association is due to the processing of the products rather than their (likely) poor nutritional quality – the foods and drinks examined in the individual studies within this paper appeared to be primarily those with high fat, salt and/or sugar content (examples given include ‘junk’ foods, fast foods, carbonated drinks, sugar sweetened beverages, sweets, chocolates, icecream, snacks/meals in front of screens…). Most of the potential mechanisms of action suggested by the authors relate to the nutritional quality of the foods/drinks rather than specific effects of processing. It is also unclear how ‘high’ and ‘low’ intakes of UPF are classified and whether this varies between individual studies.

“The authors conclusion that ‘public health strategies targeting reduced UPF intake and promotion of healthier diets should be prioritised to prevent adolescent overweight/ obesity and associated health risks’ does not change already existing approaches to healthy weight, which emphasise the importance of healthy eating and advocate limiting intakes of high fat, salt and sugar foods, in adolescents as well as other age groups.

“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.”

Prof Maria Bryant, Professor of Public Health Nutrition, University of York, said:

“This looks to be a well conducted systematic review of papers that have explored the association between UPF consumption and obesity in adolescents. The findings indicate that increased consumption is related to obesity. This remains an important area requiring research, so it’s good to see a synthesis of findings across a large number of papers that adds to the evidence base.

“It’s worth highlighting that the research does not address one of the fundamental questions in this field – which is – whether these findings are specifically related to consumption of UPFs or foods high in fat, sugar and salt (HFSS).  This is important, given that the types of UPFs listed in the studies are also all HFSS foods. It is therefore difficult to tell if the health outcome is caused by the processing or simply the nutrient profile. Understanding the independent effects of UPFs is fundamental to how we support decision making without adding confusion to public health policy and messaging. Emerging research in this area is starting to disentangle the potential independent effects (e.g. https://pmc.ncbi.nlm.nih.gov/articles/PMC12322569 and https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000001365/) but more work is required.”

‘Ultra-processed food consumption and the risk of overweight and obesity in adolescents: A systematic review and meta-analysis’ by Mekuriaw Nibret Aweke et al. was published in PLOS One at 19:00 UK Time on Wednesday 15 April 2026. 

DOI: 10.1371/journal.pone.0344873

Declared interests

Prof Gunter Kuhnle: “I am a former member of the UK Committee on Toxicity of Chemicals in Food, Consumer Products, and the Environment; a current member of the Advisory Committee on Novel Foods and Processes; the Director of the Chemical Analysis Facility at the University of Reading, which provides analytical services to academic and commercial clients; have received research funding (2010–20) from Mars for work on flavanols; and have received consultancy payments from RSM UK and EQT, paid to the University of Reading. As a member of the EFSA ANS panel (2018-2019) and the UK’s COT (2019-2025) I was involved in the evaluation of stevia glucosides.”

Dr Hilda Mulrooney: “I am a committee member of the BDA Obesity Group, Council member for Public Health for the Nutrition Society, committee member of the European Specialist Dietitians Network for Obesity and of the Obesity Management Collaborative. All these roles are unpaid.”

Prof Maria Bryant: no conflicts of interest to declare.

Dr Amanda Avery: “apart from my academic role at the University of Nottingham (Associate Professor in Nutrition & Dietetics), I also hold a position at Slimming World – Consultant Dietitian in Weight management as part of the Nutrition, Research & Health Policy team.”

Prof Jules Griffin: “I am a consultant for Sitryx, a company specialising in designing drugs to target immunometabolism. I receive funding from the Scottish Government, European Union, Medical Research Council, Biotechnology and Biological Sciences Research Council and the British Heart Foundation. I hold shares in GlaxoSmithKline and Haleon plc.”