The deadly toll of ultra-processed foods has been laid out in a global study showing junk food makes up more than half of people’s food energy consumption in some countries.
The report showed premature deaths attributable to UPFs increased significantly according to their share in a person’s diet.
Researchers called for global action to reduce junk food consumption, involving governments introducing stricter policies to create healthier diets. Addressing the impact of UPF should be a global nutrition priority, they said, as their consumption is growing in low and middle-income countries.
UPFs have been linked previously to 32 diseases, including to an increased risk of obesity, heart disease and cancer, as well as early death.
Examples of UPFs include ice cream, processed meats, crisps, mass-produced bread, some breakfast cereals, biscuits and fizzy drinks.
They are ready-to-eat-or-heat industrial formulations that are made with ingredients extracted from foods or synthesised in laboratories, with little or no wholefoods in their composition. These have gradually been replacing traditional foods and meals made from fresh and minimally processed ingredients.
Oswaldo Cruz Foundation
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, artificial colours and flavouring.
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, researchers looked at data from eight countries – Australia, Brazil, Canada, Chile, Colombia, Mexico, the UK and US – and found UPFs reached 55 per cent of people’s energy intake in the US and 53 per cent in the UK, compared with 15 per cent in Colombia and 17.4 per cent in Brazil.
Premature deaths attributable to UPFs ranged from 4 per cent of in lower consumption settings, such as Colombia, to 14 per cent of all early deaths in the UK and US, according to their mathematical modelling.
The researchers suggested that in 2017-2018, up to 124,107 premature deaths in the US could have been linked to UPFs. Over similar timeframes, the UK’s figure stood at 17,781 and Mexico 17,110.
While previous studies focused on specific dietary risk factors instead of food patterns, the current study modelled data from nationally representative dietary surveys and mortality data to link dietary patterns, considering the extent and purpose of industrial food processing, to deaths from all causes.
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 per cent increase in the participation of UPFs in the diet increases the risk of death from all causes by 3 per cent”.
He said it was is concerning that, while in high-income countries UPF consumption has been high but relatively stable for more than a decade, in low and middle-income countries consumption has continuously increased, meaning that while the attributable burden in high-income countries is currently higher, it is growing in the other nations. "This shows that policies that disincentivise the consumption of UPFs are urgently needed globally, promoting traditional dietary patterns based on local fresh and minimally processed foods," he said.
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.”
