Ultra-processed foods – such as chicken nuggets, ice cream and breakfast cereals – have been linked to early death and poor health, scientists say.
Researchers in France and Spain say the amount of such food being eaten has soared.
Their studies are not definite proof of harm but do come hot on the heels of trials suggesting ultra-processed foods lead to overeating.
Experts expressed caution but called for further investigation.
Prof Maira Bes-Rastrollo, from the University of Navarra, told BBC News: “It is said that if a product contains more than five ingredients, it is probably ultra-processed.”
Examples include: processed meat such as sausages and hamburgers • breakfast cereals or cereal bars • instant soups • sugary fizzy drinks • chicken nuggets • cake • chocolate • ice cream • mass-produced bread • many “ready to heat” meals such as pies and pizza | meal-replacement shakes
How bad were the findings?
The first study, by the University of Navarra, in Spain, followed 19,899 people for a decade and assessed their diet every other year.
There were 335 deaths during the study.
But for every 10 deaths among those eating the least ultra-processed food, there were 16 deaths among those eating the most (more than four portions a day).
The second study, by the University of Paris, followed 105,159 people for five years and assessed their diet twice a year.
It showed those eating more ultra-processed food had worse heart health.
Rates of cardiovascular disease were 277 per 100,000 people per year among those eating the most ultra-processed food, compared with 242 per 100,000 among those eating the least.
Dr Mathilde Touvier, from the University of Paris, told BBC News: “The rapid and worldwide increasing consumption of ultra-processed foods, to the detriment of less processed foods, may drive a substantial burden of cardiovascular diseases in the next decades.”
What are ultra-processed foods?
The term comes from a way of classifying food by how much industrial processing it has been through.
The lowest category is “unprocessed or minimally processed foods”, which include: • fruit • vegetables • milk • meat • legumes such as lentils • seeds • grains such as rice • eggs
“Processed foods” have been altered to make them last longer or taste better – generally using salt, oil, sugar or fermentation.
This category includes: cheese • bacon • home-made bread • tinned fruit and vegetables • smoked fish • beer
Then come “ultra-processed foods”, which have been through more substantial industrial processing and often have long ingredient lists on the packet, including added preservatives, sweeteners or colour enhancers.
What we eat has a big impact on our health, and ultra-processed foods like candy, soft drinks, pizza and chips do not contain enough of the beneficial nutrients that the body requires. The more ultra-processed foods we eat, the poorer the overall nutritional quality of our diet.
But here’s the good news. Not every food that comes in a box is ultra-processed. Confused?. But this list is a classification system called NOVA that was developed by an international panel of food scientists and researchers. It splits foods into four categories:
Unprocessed or minimally processed foods: Think vegetables, grains, legumes, fruits, nuts, meats, seafood, eggs and milk. Make these real, whole foods the basis of your diet.
Processed culinary ingredients: These items make plain vegetables and a grilled chicken breast taste a whole lot better. Examples are herbs, spices, balsamic vinegar, garlic and oil. Use these ingredients in small amounts to create fresh, home-cooked meals.
Processed foods: When ingredients such as oil, sugar or herbs are added to foods and they are packaged, the result is processed foods. Examples are simple bread, cheese, tofu, and canned tuna or beans. These foods have been altered, but not in a way that’s detrimental to health. They are convenient and help you build nutritious meals. See? Not everything in a package is bad for you!
Ultra-processed foods: Here’s the category where almost 50% of our calories come from – and where we should cut back. These foods go through multiple processes (extrusion, molding, milling, etc.), contain many added ingredients and are highly manipulated. Examples are soft drinks, chips, chocolate, candy, ice-cream, sweetened breakfast cereals, packaged soups, chicken nuggets, hotdogs, fries and more.
So do these foods damage health?
The evidence is accumulating. Increasing numbers of independent studies observe associations between ultra-processed foods and adverse health effects.
Last year, a link was made with an increased risk of cancer.
The studies have spotted a pattern between highly processed food and poor health but they cannot prove that one causes the other.
Those who ate the most ultra-processed food were also more likely to have other unhealthy behaviours, such as smoking, which the researchers tried to account for.
But Kevin McConway, a professor of statistics at The Open University, said: “One can’t be sure that everything relevant was allowed for.
“These studies do increase my confidence that there’s something real behind these associations – but I’m still far from sure.”
Why might ultra-processed foods be bad?
The first trial of ultra-processed foods showed they led people to eat more and put on weight.
Researchers at the US National Institutes of Health monitored every morsel of food that volunteers ate for a month.
And when given ultra-processed food, they ate 500 calories a day more than when they were given unprocessed meals.
Other suggestions include:
- They are energy dense but lacking in nutrients and fibre
- While the additives in food have been safety tested, it may be unhealthy to consume lots of additives from different foods
- People eat more because they’re easy to eat
- They push healthier foods such as fruit and vegetables out of diets – who wants a banana when you can have ice cream?
These ideas still need researching.
How can I cut back on ultra-processed foods?
Cook more often: One major change in dietary patterns in the last 70 years has been the decline of home cooked meals, and the increase in ultra-processed foods. Tip the balance! Cook at home more often, without using ultra-processed ingredients (heating up frozen fried chicken doesn’t count).
Dine with friends and family: Real food, real talk, good company. That’s a winning combination for dinner – and studies show that people who dine together have better eating habits, such as enjoying more vegetables, fewer soft drinks, and less deep-fried food.
Is the ultra-processed label a load of nonsense?
Describing foods as ultra-processed has a lot of critics.
Dr Gunter Kuhnle, an associate professor in nutrition and health at the University of Reading, said the studies were important and warranted further investigation.
But the labelling of food as ultra-processed could be inconsistent.
He said: “It is also not obvious why salami is considered to be ultra-processed, yet cheese, which often requires considerably more processing steps and additives, is not.
“The classification combines a wide range of foods with very different potential impacts on health, which limits its usefulness as a basis for recommendations.”
The studies were published in the British Medical Journal.