BBCThem Black Monster Many nutritionists recommend mass-produced but tempting foods like chicken nuggets, packaged snacks, soda, ice cream and even sliced whole wheat bread.
So-called ultra-processed foods (UPF) It accounts for 56% of calories consumed in the UKand that figure is even higher for children and people living in poorer areas.
UPFs are defined by how many industrial processes they go through and the number of—often unpronounceable—ingredients on their packaging. Most are high in fat, sugar, or salt; many you might call fast food.
What unites them is their synthetic look and taste, which has made them a target for some clean-living advocates.
There’s growing evidence that these foods aren’t good for us, but experts don’t agree on exactly how or why they affect us, and it’s not clear that science will give us an answer anytime soon.
Recent studies show that there are many common health problems such as cancer, heart disease, obesity and depression. connected No evidence yet for UPFs caused by them.
For example, at a recent meeting of the American Society for Nutrition in Chicago, an observational study of more than 500,000 people in the U.S. was presented. It found that those who ate the most UPF had about a 10% greater chance of dying, even after accounting for their body mass index and overall diet quality.
In recent years, many other observational studies have shown a similar link – but that is not the same as proving that: How Determining whether food processing causes health problems or which aspect of these processes is responsible.
So how do we get to the truth about ultra-processed foods?
Dr Nerys Astbury, senior researcher in nutrition and obesity at the University of Oxford, suggests that the type of research needed to definitively prove that UPFs cause health problems would be extremely complex.
He would have to compare a large number of people on two diets – one high in UPF, the other low in UPF, but exactly matched in terms of calories and macronutrient content. That would be devilishly difficult to do.
Participants will need to be kept under lock and key and their food intake will need to be tightly managed. The study will also need to enroll people with similar diets as a starting point. Logistically, this will be extremely challenging.
To rule out the possibility that people who consume less UPF simply have a healthier lifestyle by exercising more or sleeping more, participants in the groups need to have very similar habits.
“This would be an expensive study, but you could see changes from the diets relatively quickly,” Dr. Astbury says.
Funding for such research can also be difficult to obtain, and there may be accusations of conflict of interest, as researchers motivated to conduct such trials may have an idea of what they want the results to be before they begin.
These trials couldn’t go on for very long anyway – too many participants would probably drop out. It wouldn’t be practical to tell hundreds of people to follow a strict diet for more than a few weeks.
So what could these hypothetical experiments actually prove?
Getty ImagesDuane Mellor, leader in nutrition and evidence-based medicine at Aston University, says nutritional scientists cannot prove that particular foods are good or bad, or what effects they have on an individual. They can only indicate potential benefits or risks.
“The data doesn’t show more or less,” he says, calling claims to the contrary “weak science.”
Another option would be to look at the effects of common food additives found in UPFs on a laboratory model of the human gut, something scientists are working on extensively.
But there’s a broader problem: confusion over what counts as UPF.
They usually contain more than five ingredients, few of which you can find in a typical kitchen cupboard.
Instead, they are often made from inexpensive ingredients like modified starches, sugars, oils, fats, and protein isolates. Flavor enhancers, colors, emulsifiers, sweeteners, and glazing agents are then added to make them more appealing to the taste buds and eyes.
These range from the obvious (sugared cereals, soda, slices of American cheese) to the perhaps more unexpected (supermarket hummus, low-fat yogurts, some muesli).
And that raises questions: How useful is a label that puts chocolate bars in the same league as tofu? Might some UPFs affect us differently than others?
BBC News spoke to the Brazilian professor who coined the term “ultra-processed food” in 2010 to find out more.
Prof. Carlos Monteiro also developed the Nova classification system, which includes “whole foods” (like legumes and vegetables) at one end of the spectrum, followed by “processed kitchen ingredients” (like butter) and then “processed foods” (like canned tuna and salted nuts) and extending all the way to UPFs.
The system was developed after obesity continued to rise in Brazil as sugar consumption fell, and Prof. Monteiro wondered why. He believes that our health is affected not only by the nutritional content of the food we eat, but also by the industrial processes used to make and preserve it.
He says he didn’t expect this huge interest in UPFs, but claims they “contributed to a paradigm shift in nutritional science.”
But many nutritionists say fears of UPF are overblown.
Gunter Kuhnle, professor of nutrition and food science at the University of Reading, says the concept is “vague” and its message is “negative”, leaving people confused and fearful of food.
It is true that there is currently no concrete evidence that the way food is processed is harmful to our health.
Processing is something we do every day; chopping, boiling and freezing are all processes and they are not harmful.
And when food is processed on a large scale by manufacturers, it ensures that the food is safe, keeps longer and reduces waste.
Take frozen fish fingers for example. These use up fish scraps, provide healthy food for kids and save parents time – but they still count as UPF.
Getty ImagesWhat about meat substitutes like Quorn? Sure, they don’t resemble the original material they’re made from (and therefore fall under Nova’s UPF designation) but they’re seen as healthy and nutritious.
“If you make a cake or brownie at home and compare it to one that comes in a packet with flavour enhancers, do I think there is any difference between those two foods? No, I don’t,” says Dr. Astbury.
The Food Standards Agency, the body responsible for food safety in the UK, acknowledges reports that people who consume too much UPF have a higher risk of heart disease and cancer, but says it will not take action until there is evidence that UPFs cause specific harm.
Last year, the government’s Scientific Advisory Committee on Nutrition (SACN) looked at the same reports and concluded there were “uncertainties about the quality of the available evidence”. It also had some concerns about the practical application of the Nova system in the UK.
Prof. Monteiro is most concerned about heat-intensive processes, such as the production of breakfast cereals and puff pastry, which he claims “degrade the natural food matrix.”
He points to a small study that suggests this leads to nutrient loss, which makes us feel less full, so we’re more likely to make up for the deficit with extra calories.
It’s also hard to ignore the smugness and—if whispered—snobbery around UPFs, which can make people feel guilty about eating them.
Dr Adrian Brown, a registered dietitian and senior research fellow at University College London, says it is unhelpful to demonize a single type of food, especially when what and how we eat is so complex. “We need to be careful about the moralisation of food,” he says.
Living a life without UPF can be expensive, and cooking meals from scratch takes time, effort, and planning.
A latest Food Foundation report It found that healthier foods cost twice as much per calorie as less healthy foods, and that the poorest 20% of the UK population would need to spend half their disposable income on food to meet the government’s food needs. Healthy Nutrition SuggestionsThe cost to the richest will be only 11%.
I asked Prof. Monteiro if it was possible to live without UPFs.
“The question here should be: is it possible to stop the increasing consumption of UPFs?” he says. “My answer is: it is not easy, but it is possible.”
Many experts say the current traffic light system on food labels – marking high, medium and low levels of sugar, fat and salt – is a simple and useful guide when shopping.
For those who are hesitant to shop, there are now apps on smartphones like the Yuka app. With this app, you can scan the barcode and see how healthy the product is.
And of course there’s the advice you already know – eat more fruits, vegetables, whole grains and beans, while cutting back on fatty and sugary snacks. Whether or not scientists can prove that UPFs are harmful, it’s still a good idea to stick with them.
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