People who eat more ultra-processed food (UPF) may have a higher risk of developing type 2 diabetes, a study has suggested.

Researchers found that for every 10% increase in the proportion of a person's total daily food intake that comes from UPF, there is a 17% increase in the risk of developing a new case of type 2 diabetes. This risk may be reduced by replacing UPF with less processed foods.

The findings are published in The Lancet Regional Health – Europe and adds to a growing body of evidence that shows reducing intake of specific UPF can lower the risk of type 2 diabetes.

UPF includes foods such as processed meats, ready meals, savoury snacks, sweets and desserts and artificially sweetened drinks. The degree of processing in foods is classified using the NOVA system, which divides foods into unprocessed or minimally processed foods (MPF) such as eggs, milk, and fruit; processed culinary ingredients (PCI) such as salt, butter and oil; processed foods (PF) like tinned fish, beer and cheese; and ultra-processed food.

Researchers from University College London (UCL), the University of Cambridge and Imperial College London examined the relationship between the degree of food processing and type 2 diabetes risk, including which kinds of UPF might be high-risk.

Participants were part of the European Prospective Investigation into Cancer and Nutrition (EPIC) and included 311,892 individuals from eight European countries. Participants’ diets were assessed using questionnaires over an average period of 10.9 years, and the proportion of processed food consumed was determined using the NOVA classification. Statistical models allowed the researchers to assess the association between MPF, PCI, PF and UPF intake and the risk of developing type 2 diabetes.

Over the study period, 4.5% of the participants (n=14,236) developed type 2 diabetes. The researchers found that every ten per cent increase in the amount of UPF in a person’s diet is linked to a 17% increase in type 2 diabetes risk.

Replacing UPF with less processed alternatives was associated with lower incident type 2 diabetes. By substituting 10 per cent of UPF in the diet with 10% of MPF/PCI, the risk of developing type 2 diabetes can be reduced by 14%. The exact causes of the link between UPF and type 2 diabetes are unconfirmed, although previous research suggests that overconsumption and weight gain play a part.

Dr Samuel Dicken, first author of the study from UCL, said: ‘We know that ultra-processed foods are associated with a higher risk of certain diseases such as type 2 diabetes. As expected, our findings confirm this link.’

He added: ‘Most studies to date only consider UPF as a whole, but we also suspect that there may be different risks associated with different types of UPF, and the risks of other processing groups have not been well researched. Our analysis goes a step further than previous studies by looking at all four processing groups in the NOVA classification to gauge the impact on type 2 diabetes risk when we substitute UPF with less processed foods, as well as looking at nine UPF subgroups.’

Analysis of the UPF subgroups showed that savoury snacks, animal-based products, ready meals, and sugar-sweetened and artificially sweetened beverages were associated with higher incidence of type 2 diabetes.

The findings also show that foods such as breads, biscuits and breakfast cereals, sweets and desserts, and plant-based alternatives are linked to a lower risk of developing type 2 diabetes.

Professor Rachel Batterham, senior author of the study from UCL Division of Medicine, added: ‘The UPF subgroup analysis in this study has been revealing and confirms that not all foods categorised as UPF are alike in terms of the health risks associated with them. Breads and cereals, for example, are a staple of many people’s diets. Based on our results, we should treat them differently to savoury snacks or sugary drinks in terms of the dietary advice we provide.’

A version of this article was first published by our sister title Nursing in Practice