Why We May Never Know the Truth About Ultra-Processed Foods

Per Filipa RoxbyBBC News

They are the bête noire of many nutritionists – mass-produced but tasty foods like chicken nuggets, packaged chips, soda, ice cream or even slices of whole-grain bread.

So-called ultra-processed foods (UPFs) account for 56% of calories consumed in the UK, and this figure is higher for children and people living in poorer areas.

UPFs are defined by how many industrial processes they have undergone and the number of ingredients—often unpronounceable—in their packaging. Most are high in fat, sugar, or salt; many you would call fast food.

What unites them is their synthetic appearance and taste, which has made them a target for some advocates of a healthier lifestyle.

There’s a growing body of evidence that these foods aren’t good for us. But experts can’t agree on exactly how they affect us or why, and it’s unclear whether science will give us an answer any time soon.

Although recent research shows that many widespread health problems, including cancer, heart disease, obesity, and depression, are linked to UPAs, there is still no proof that they are caused by them.

For example, a recent meeting of the American Society for Nutrition in Chicago featured an observational study of over 500,000 people in the U.S. It found that those who ate the most UPFs had an approximately 10 percent higher 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’s not the same as proving that the way foods are processed causes health problems or determining which aspect of those processes might be to blame.

So how can we find out the truth about ultra-processed foods?

The kind of studies needed to definitively prove that UPFs cause health problems would be extremely complex, suggested Dr Nerys Astbury, a senior research fellow in diet and obesity at the University of Oxford.

It would be necessary to compare a large number of people on two diets—one high in UPFs and one low in UPFs, but exactly matched in calorie and macronutrient content. This would be terribly difficult to actually do.

Participants would need to be kept under lock and key so that their food intake could be tightly controlled. The study would also need to recruit people with similar diets as a starting point. This would be extremely challenging logistically.

And to counter the possibility that people who eat fewer UPFs might have healthier lifestyles, such as exercising more or sleeping more, participants in the groups would need to have very similar habits.

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

Funding for this type of research can also be difficult to obtain. There may be accusations of conflicts of interest, as researchers motivated to conduct this type of trial may have an idea of ​​what they want the conclusions to be before they begin.

In any case, these trials could not last very long – many participants would probably drop out. It would be impractical to tell hundreds of people to stick to a strict diet for more than a few weeks.

And what could these hypothetical tests actually prove?

Duane Mellor, head of nutrition and evidence-based medicine at Aston University, said nutrition scientists cannot prove that specific foods are good or bad or what effect they have on an individual. They can only show potential benefits or risks.

“The data doesn’t show more or less,” he said. Claims to the contrary are “poor science.”

Another option would be to observe the effect of common food additives present in UPFs on a laboratory model of the human gut – something scientists are busy doing.

However, there is a broader issue: the amount of confusion surrounding what actually counts as UPFs.

They usually include more than five ingredients, few of which you would find in a typical kitchen cupboard.

Instead, they are typically made from inexpensive ingredients such as modified starches, sugars, oils, fats, and protein isolates. Then, to make them more appealing to the palate and eyes, flavor enhancers, colors, emulsifiers, sweeteners, and glazing agents are added.

They range from the obvious (sugary breakfast cereals, soda, slices of American cheese) to perhaps the more unexpected (supermarket hummus, low-fat yogurts, some mueslis).

And that raises the questions: How useful is a label that puts chocolate bars in the same league as tofu? Could 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” (like legumes and vegetables) at one end of the spectrum, through “processed culinary ingredients” (like butter), through “processed foods” (things like canned tuna and salted nuts) all the way to UPFs.

The system was developed after obesity in Brazil continued to rise as sugar consumption fell, and Prof. Monteiro wondered why. He believes our health is influenced not only by the nutritional content of the foods we eat, but also by the industrial processes used to make and preserve them.

He said he did not expect the current amount of attention on UPFs, but said “they are contributing to a paradigm shift in nutrition science.”

However, many nutritionists say the fear of UPFs is overblown.

Gunter Kuhnle, professor of nutrition and food science at the University of Reading, said the concept was “vague” and the message it conveyed was “negative”, leaving people feeling confused and afraid of food.

It is true that there is currently no concrete evidence that the way foods are 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 food is safe, preserved for longer, and that waste is reduced.

Take frozen fish sticks, for example. They use up leftover fish, provide healthy food for kids, and save parents time—but they still count as UPFs.

What about meat replacement products like Quorn? Sure, they don’t look like the original ingredient they’re made from (and therefore fall under the New UPF definition), but they’re seen as healthy and nutritious.

“If you make a cake or brownie at home and compare it to one that already comes in a packet with flavor enhancers, do I think there’s any difference between those two foods? No, I don’t,” Dr. Astbury told me.

The UK’s food safety body, the Food Standards Agency, has acknowledged reports that people who eat a lot of UPFs are at increased risk of heart disease and cancer, but said it would not take any action on UPFs until there was evidence they caused specific harm.

Last year, the government’s Scientific Advisory Committee on Nutrition (SACN) reviewed the same reports and concluded that there were “uncertainties surrounding the quality of the available evidence”. It also had some concerns around the practical application of the Nova system in the UK.

In turn, Prof. Monteiro is more concerned about processes that involve intense heat, such as the production of breakfast cereal flakes and balls, which, according to him, “degrade the natural food matrix”.

He points to a small study that suggests this results in nutrient loss and therefore leaves us feeling less satisfied, meaning we’re more tempted to make up for the deficiency with extra calories.

It’s also hard to ignore the growing sense of self-righteousness and — whisper it — snobbery surrounding ultra-processed sunscreens, which can make people feel guilty about eating them.

Dr Adrian Brown, a specialist nutritionist and senior research fellow at University College London, said demonising one type of food is unhelpful, especially when what and how we eat is such a complicated issue.

“We have to be aware of the moralization of food,” he said.

Living a life without FPS can be expensive—and preparing meals from scratch takes time, effort, and planning.

A recent report from the Food Foundation found that healthier foods were twice as expensive as less healthy foods per calorie, and the poorest 20% of the UK population would need to spend half their disposable income on food to meet the government’s healthy diet recommendations. It would cost the richest just 11% of them.

I asked Prof. Monteiro if it was possible to live without UPFs.

“The question here should be: is it feasible to stop the growing consumption of UPFs?” he said. “My answer is: it’s not easy, but it is possible.”

Many experts say the current traffic light system on food labels (which signals high, medium and low levels of sugar, fat and salt) is simple and useful enough as a guide when shopping.

There are now smartphone apps available for the unsure shopper, such as the Yuka app, which lets you scan a barcode and get a breakdown of the healthiness of the product.

And of course, there’s the advice you already know: Eat more fruits, vegetables, whole grains and beans, while cutting back on fat and sugary snacks.

Keeping this in mind remains a good idea regardless of whether or not scientists prove that UPFs are harmful.

– BBC