Experts behind the research said they believe there is a relationship between people eating UPFs and an increased risk of early death.
UPFs have been linked previously to poor health, including to an increased risk of obesity, heart disease, cancer and early death.
Examples of UPFs include ice cream, processed meats, crisps, mass-produced bread, some breakfast cereals, biscuits and fizzy drinks.
UPFs often contain high levels of saturated fat, salt, sugar and additives, which experts say leaves less room in people’s diets for more nutritious foods.
UPFs also tend to include additives and ingredients that are not used when people cook from scratch, such as preservatives, emulsifiers and artificial colours and flavours.
However, some experts say it is not clear why UPFs are linked to poor health and question whether this is because of processing or because people are opting for foods high in fat, sugar and salt rather than more nutritious options.
In the new study, published in the American Journal of Preventive Medicine, experts call on governments to issue dietary recommendations aimed at cutting consumption of UPFs.
They looked at data from eight countries around the world and found UPFs reached 53% of people’s energy intake in the UK – the second highest in the study after 55% in the US.
UPFs affect health beyond the individual impact of high content of critical nutrients (sodium, trans fats, and sugar) because of the changes in the foods during industrial processing and the use of artificial ingredients
Dr Eduardo Nilson, researcher
Premature deaths attributable to UPFs ranged from 4% of premature deaths in lower consumption settings, such as Colombia, up to 14% of premature deaths in the UK and US, according to their mathematical modelling.
The researchers suggested that in 2018/19, some 17,781 premature deaths in the UK could have been linked to UPFs, according to their model.
Lead investigator of the study Eduardo Nilson, from the scientific body the Oswaldo Cruz Foundation in Brazil, said: “UPFs affect health beyond the individual impact of high content of critical nutrients (sodium, trans fats, and sugar) because of the changes in the foods during industrial processing and the use of artificial ingredients, including colourants, artificial flavours and sweeteners, emulsifiers, and many other additives and processing aids, so assessing deaths from all causes associated with UPF consumption allows an overall estimate of the effect of industrial food processing on health.”
Dr Nilson said the study found “each 10% increase in the participation of UPFs in the diet increases the risk of death from all causes by 3%”.
Stephen Burgess, statistician in the MRC Biostatistics Unit at the University of Cambridge, said the study was observational and could not prove cause.
“This type of research cannot prove that consumption of ultra-processed foods is harmful, but it does provide evidence linking consumption with poorer health outcomes,” he said.
“It is possible that the true causal risk factor is not ultra-processed foods, but a related risk factor such as better physical fitness – and ultra-processed foods is simply an innocent bystander.
“But when we see these associations replicated across many countries and cultures, it raises suspicion that ultra-processed foods may be more than a bystander.”
More research is needed to ascertain a causal link between UPF and disease and to establish the mechanisms involved
Dr Nerys Astbury, University of Oxford
Nerys Astbury, associate professor from the University of Oxford, said it is known that consuming diets higher in calories, fat and sugar can have detrimental effects on health, including premature mortality.
“This study adds to the body of evidence on the association between UPF and ill health and disease,” Dr Astbury added.
“However, many UPF tend to be high in these nutrients, and studies to date have been unable to determine with certainty whether the effects of UPF are independent of the already established effects of diets high in foods which are energy dense and contain large amounts of fat and sugar.
“The authors of the study conclude that advice to reduce UPF consumption should be included in national dietary guideline recommendations and in public policies.
“However, rushing to add recommendations on UPF to these recommendations is not warranted based on this study in my opinion.”
She said the Nova system, which defines foods according to different levels of food processing, “has many limitations, including arbitrary definitions and overly broad food categories…”.
She added: “More research is needed to ascertain a causal link between UPF and disease and to establish the mechanisms involved.”