We’ll probably never know the truth about ultra-processed foods

they are black Beast According to many nutritionists – mass-produced but overly palatable foods such as chicken nuggets, packaged snacks, fizzy drinks, ice cream or even sliced ​​brown bread.

UPFs are defined by how many industrial processes they have gone through and the ingredients on their packaging – often unpronounceable. Most are high in fat, sugar or salt; many are what you would call fast food.

What unites them is their artificial appearance and taste, which has made them a target of some clean lifestyle advocates.

There’s growing evidence that these foods aren’t good for us. But experts don’t agree on how they affect us or why, and it’s not clear whether science is going to give us the answers in the near future.

While recent research suggests that a wide variety of health problems, including cancer, heart disease, obesity, and depression, are linked As for UPFs, there is no evidence, yet, that they are Reason By them.

For example, an observational study of more than 500,000 people in the U.S. was presented at a recent meeting of the American Society for Nutrition in Chicago. It found that those who ate the most UPF were about 10% more likely to die, even after taking into account their body-mass index and overall quality of diet.

In recent years, several other observational studies have shown a similar relationship – but that’s not the same as proving it How Exploring how processed foods are likely to cause health problems, or what aspects of those processes may be to blame.

So how then can we know the truth about ultra-processed foods?

Dr Nerys Astbury, a senior researcher in diet and obesity at the University of Oxford, suggests that the kind of study needed to definitively prove that UPFs cause health problems would be extremely complex.

This would require comparing a large number of people on two diets – one with high UPFs and the other with low UPFs, but with exactly matched calorie and macronutrient intakes. This would be extremely difficult indeed.

Participants would have to be kept under lock and key so that their food intake could be closely monitored. The study would also have to include people with similar diets in the initial phase. This would be logistically very challenging.

And to counter the possibility that people who eat less UPF might have a healthier lifestyle, such as exercising more or getting more sleep, the habits of the participants in the groups should be very similar.

“It would be expensive research, but you could see changes in diet relatively quickly,” says Dr Astbury.

It can also be difficult to raise funds for such research. Allegations of conflict of interest may arise, since researchers motivated to run such trials know before they begin what conclusions they want to draw.

These trials can’t last very long anyway – many participants will probably drop out. Asking hundreds of people to stick to a strict diet for more than a few weeks would be impractical.

And, after all, what can these hypothetical tests actually prove?

Duane Mellor, head of nutrition and evidence-based medicine at Aston University, says nutrition scientists cannot prove whether a particular food is good or bad or what effect it has on a person. They can only show potential benefits or risks.

“The data show nothing more or less,” he says, adding that claims to the contrary are “bad science.”

Another option would be to look at the effects of common food additives present in UPF on a laboratory model of the human gut – which scientists are busy working on.

A broader issue, however, is that there is a great deal of confusion about what exactly is considered a UPF.

Typically, these contain no more than five ingredients, some of which you’ll find in a typical kitchen cupboard.

Instead, they are usually made from cheaper ingredients like modified starches, sugars, oils, fats and protein isolates. Then, to make them more appealing to the taste buds and the eyes, flavor enhancers, colors, emulsifiers, sweeteners and glazing agents are added.

These range from the obvious ones (sugary breakfast cereals, carbonated drinks, slices of American cheese) to the perhaps more unexpected ones (supermarket hummus, low-fat yogurt, some muesli).

And that raises the question: How helpful is a label that equates chocolate bars with tofu? Might some UPFs affect us differently than others?

To find out more, BBC News spoke to the Brazilian professor who coined the term “ultra-processed food” in 2010.

Professor Carlos Monteiro also developed the NOVA classification system, which ranges from “whole foods” (such as legumes and vegetables) at one end of the spectrum to “processed culinary ingredients” (such as butter) and then “processed foods” (things like canned tuna and salted nuts) at the other end of the spectrum.

The system was developed when obesity continued to rise in Brazil despite a decline in sugar consumption and Professor Monteiro wondered why this happened. He believes that our health is affected not only by the nutrient content of the food we eat, but also by the industrial processes used to produce and preserve it.

He said he did not expect UPF to receive as much attention as it currently does, but claims it “is contributing to a paradigm shift in nutritional science”.

However, many nutrition experts say the UPF scare is overblown.

Gunter Kuhnle, professor of nutrition and food science at the University of Reading, says the concept is “ambiguous” and the message it sends is “negative”, leaving people feeling confused and fearful about food.

It is true that at present there is no concrete evidence that the way food is processed harms our health.

Processing is something we do every day – cutting, boiling and freezing are all processes, and these things are not harmful.

And when food is processed on a large scale by manufacturers, it helps ensure that the food is safe, lasts longer and there is less wastage.

Take frozen fish fingers for example. They use up leftover pieces of fish, give kids some healthy food and save parents time – but they still count as UPFs.

And what about products used as meat substitutes like Quorn? Granted, they don’t look like the original ingredient they’re made from (and therefore fall under UPF’s NOVA definition), but they’re considered healthy and nutritious.

“If you make a cake or brownies at home and compare it to a cake or brownies that come in a package and have added flavourings, do I think there’s a difference between the two foods? No, I don’t,” Dr Astbury told me.

The Food Standards Agency, the body responsible for food safety in England, acknowledges reports that people who eat large amounts of UPFs have a higher risk of heart disease and cancer, but says it will not take action on UPFs unless there is evidence they cause significant harm.

Last year, the government’s Scientific Advisory Committee on Nutrition (SACN) looked at the same reports and concluded that 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.

Professor Monteiro is most concerned about processes involving intense heat, such as the manufacture of breakfast cereal flakes and puffs, which he claims “degrade the natural food matrix.”

He cites a small study that suggests this leads to a loss of nutrients and therefore makes us feel less full, meaning we’re more prone to make up for the loss with extra calories.