Ultraprocessed foods could be killing more Americans than fentanyl, a new study has found.

The unhealthy food group, popularised for its convenience, often contains high levels of sugar, salt and unhealthy fats – and are believed to make up over 70 per cent of the US food supply.

Australians also consume a large amount of ultra-processed foods, also known as UPFs, with research suggesting they make up around 40 to 42 per cent of their daily energy intake.

Alarmingly, consumption of ultraprocessed foods has also been tied to a growing list of health conditions, including obesity, type 2 diabetes, heart disease and some cancers.

Now, researchers have examined data from the US and seven other countries to estimate the percentage of premature, preventable deaths due to the consumption of UPFs like packaged snacks, sugary drinks, processed meats and sweetened breakfast cereals, the New York Post reports.

“We looked at the risk of a person dying from eating more ultra-processed foods between the ages of 30 and 69, a time when it would be premature to die,” study co-author Carlos Augusto Monteiro, emeritus professor of nutrition and public health in the School of Public Health at Brazil’s University of São Paulo, told CNN.

Monteiro’s team found that the risk of early death rises by nearly 3 per cent for every 10 per cent increase in calories from UPFs.

The findings were published Monday in the American Journal of Preventive Medicine in an article titled, “Premature Mortality Attributable to Ultraprocessed Food Consumption in 8 Countries”.

Prior research has linked UPFs to 32 negative health outcomes, including elevated risks of heart disease, cancer, Type 2 diabetes and mental health woes.

Some 124,000 premature US deaths were attributable to UPF consumption in 2018, said Eduardo Augusto Fernandes Nilson, lead investigator of the new study.

To compare, nearly 74,000 Americans died from a fentanyl overdose in 2022

Fernandes Nilson and his colleagues built a computer model that estimated percentages of UPF-related early deaths based on data from nearly 240,000 people and almost 15,000 deaths.

The results ranged from 4 per cent in countries with lower UPF consumption (Colombia) to almost 14 per cent in countries with higher UPF consumption (the UK and US).

The other countries studied were Brazil (low consumption), Chile and Mexico (intermediate) and Australia and Canada (high).

“The findings support that ultra-processed food intake contributes significantly to the overall burden of disease in many countries, and its reduction should be included in national dietary guideline recommendations and addressed in public policies,” the researchers wrote in their paper.

However, the study could not determine if the deaths were “caused by UPF consumption,” nutrition scientist Nerys Astbury – an associate professor of diet and obesity at the UK’s University of Oxford who was not involved in the study – pointed out to CNN.

The research also drew criticism from Sarah Gallo – senior vice president of product policy for the Consumer Brands Association, which represents the food industry.

“This is another example of a misleading study that will ultimately lead to consumer confusion. Currently, there is no scientific agreement on the definition of ultra-processed foods,” Gallo told the New York Post.

“Demonising convenient, affordable and shelf-ready food and beverage products could limit access to and cause avoidance of nutrient-dense foods, resulting in decreased diet quality, increased risk of food-borne illness and exacerbated health disparities.”