Fears about ultra-processed foods (UPF) “could mean people eat even less healthily”, the researchers warned.
In recent years, UPFs, which are often high in salt, sugar and saturated fat, have been linked in studies to an increased risk of obesity, heart disease, cancer and premature death.
Examples may include cookies, ice cream, processed meats, chips, mass-produced bread, soft drinks, and some breakfast cereals.
However, two experts have argued that research on UPFs is still in its early stages and more needs to be known before people are told to stop taking them.
They also warned that several UPFs, such as baked beans, vegetable-based pasta sauces, and some soups, are actually very nutritious and can contribute to a healthy diet.
In recent years, UPFs, which are often high in salt, sugar and saturated fat, have been linked in studies to an increased risk of obesity, heart disease, cancer and premature death.
Food experts say some UPF can be “part of a healthy diet.” Baked beans, fish fingers and whole wheat bread are sufficient, according to the British Nutrition Foundation (BNF). Tomato-based pasta sauces, whole grain breakfast cereals and fruit yoghurts are also “healthier processed foods”, the charity claims.
The scientists, from the universities of Aberdeen and Liverpool, said the focus of public health guidelines should remain a diet rich in fruit, vegetables and whole grains, while limiting foods high in fat, sugar and salt. .
In the new paper, published in the journal PLOS Medicine, they argued that the least well-off people could be the most affected by any general health warning about UPFs without more scientific evidence.
Professor Eric Robinson from the University of Liverpool said: “Foods classified as ultra-processed which are high in fat, salt and/or sugar should be avoided, but several ultra-processed foods are not.
“We should think very carefully about what advice is given to the public, rather than providing simplified and potentially misleading messages that end up in the headlines.”
In general, UPFs tend to include additives and ingredients that aren’t used when people cook from scratch, such as preservatives, emulsifiers, and artificial colors and flavors.
Some experts say it’s unclear why UPFs are linked to poor health and question whether this is due to processing, additives or because people tend to eat other, less nutritious foods.
The article states that there is a potential “social cost to many people with more limited resources” in eliminating convenient options.
Meanwhile, there could be negative impacts on the mental health of “those who are health-conscious or living with eating disorders, especially if social circumstances make it difficult to avoid UPF.”
Professor Alexandra Johnstone, from the University of Aberdeen, said: “We must guard against the possibility that people in our society who are already most at risk of not being able to afford to eat healthily will not be left even worse off. as we continue to investigate the links between some ultra-processed foods and poor health.
“We need more high-quality mechanistic research in humans, using controlled diets, to uncover the effects of nutrient profiling and ultraprocessing per se.”
The Nova system, developed by scientists in Brazil more than a decade ago, divides foods into four groups based on the amount of processing they have gone through. Unprocessed foods include fruits, vegetables, nuts, eggs, and meat. Processed culinary ingredients, which are not typically eaten alone, include oils, butter, sugar, and salt.
The article concluded: ‘Based on the balance of current evidence, we do not believe it is appropriate to advise consumers to avoid all UPFs.
“We look forward to further evidence to guide consumers on the need to limit consumption of specific foods based on their degree or type of processing.”
Commenting on the study, Dr Hilda Mulrooney, professor of nutrition and health at London Metropolitan University, added: ‘This is an important and timely paper, given the current level of interest in UPF and its potential effects on health.
‘It is important to recognize the fact that, for some groups in particular, foods classified as UPF make very significant contributions to nutrient intake, and this would be difficult to achieve otherwise.
‘Much of the available research shows associations between UPF and health outcomes and cannot demonstrate causality.
“This distinction is important, given that many UPFs (e.g. breakfast cereals and breads) contribute substantially to nutrient intake in the UK population.”