Ultra-processed foods are linked to 32 adverse health effects including cardiovascular diseases, cancers, and Type 2 diabetes.

That's according to a large new study published in the British Medical Journal (BMJ) that adds to growing research on the harms of foods that typically include five or more ingredients and several additives.

Common ultra-processed foods include ice cream, crisps, breakfast cereals, flavoured yoghurts, and biscuits, according to the British Heart Association.

An international team of researchers from Australia, the US, France and Ireland contributed to the umbrella review of 45 analyses that included a total population of 9.8 million participants.

“This is an important review giving us high-level recent data that calls for clear policy discussion and ultimately action to make it clear to the population what foods are ultra-processed and harmful to health," Amelia Lake, a professor of public health nutrition at Teesside University who was not involved in the study, said in a statement.

"This is a live and lively debate but we have strong knowledge around the harmful effects of diets high in fat, high in sugar, high in salt on our health.

“This is good quality research bringing together recent evidence (within 3 years), there are always issues around how dietary data is collected but the authors have reviewed the evidence and graded its quality," she added.

'Harmful to most if not all body systems'

In a linked editorial, Carlos Monteiro, a professor at the University of Sao Paulo in Brazil, wrote that the authors found "diets high in ultra-processed food may be harmful to most—perhaps all—body systems".

He added that these foods are not "merely modified" but often include "chemically manipulated cheap ingredients" such as modified starches, sugars and fats with little whole food.

"No reason exists to believe that humans can fully adapt to these products. The body may react to them as useless or harmful, so its systems may become impaired or damaged, depending on their vulnerability and the amount of ultra-processed food consumed," Monteiro added.

These foods are increasingly becoming part of diets globally, the authors said, making up more than half of daily caloric intake in the US and UK.

"We note the consistent trend linking ultra-processed foods to poor health outcomes is sufficient to warrant the development and evaluation of government-led policy and public health strategies aimed at targeting and reducing dietary exposure to ultra-processed foods," Melissa Lane, the lead author of the study from Deakin University, said in a social media post.

The researchers also assessed the credibility of the analyses' evidence.

They found that the strongest evidence revealed direct links between eating ultra-processed foods and a higher risk of death, cardiovascular disease-related mortality, mental health problems, obesity, and type 2 diabetes.

They said that further randomised controlled trials are needed to determine causality, stating that there are several limitations to this type of overall review.

The inclusion of research with different methods of assessing diet for instance leads to "an inevitable measurement bias".

They also pointed out that some ultra-processed foods may present a higher risk than others, but said that overall these foods are consistently linked to a higher risk of chronic diseases.