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Are ultra-processed foods really as bad as they seem?

Selection of packaged foods, like you'd find in a supermarket

Ultra-processed foods (UPF) have received more than their fair share of bad press in recent years with the vast majority of it being extremely negative. In light of this I wanted to uncover with this post why this might be and perhaps present some alternative realities around these besmirched foods.


What are ultra-processed foods?


The manipulation of ingredients which allows us to preserve foods and make them safe and easier to eat dates back thousands of years. Early methods of processing include fermenting, roasting on open fires, drying and salting. Canning, freezing and more technical modern methods of processing include vacuum packing, UV surface treatment and power ultrasound. All the techniques listed above allow us to extend the shelf life of foods, make them safer to eat and easier for us to digest. Historical methods and those that have incrementally appeared over time have allowed civilisation to get where it is today (and, by-the-by, also allowed women to get out of the kitchen and contribute to society!).


One definition of processed foods, as defined by the NOVA classification of food processing states that UPF are: foods which usually contain 5 or more ingredients and are often made to industrial formulations, therefore often not resembling the original food. They include processed foods that have additives to enhance taste or appearance such as sliced bread and sweetened yoghurt.


In more palatable terms UPF are basically foods you wouldn't be able to make at home because of their manufacturing process or the ingredients used in them. However, using this system to work out whether any individual food counts as minimally processed or ultra-processed is tough - peanut butter doesn't resemble a peanut in the slightest and the structure has been totally changed making it more easy to consume, so what is it?!*


*Most peanut butters would be considered processed culinary ingredients, however depending on the recipe some may be considered processed or ultra-processed.


Where has the hate come from?


There are many, many claims made around the harm that UPF do to our health and even suggestions that consumption of UPF is a leading cause of death. However, I want to state upfront that this claim is most likely to be a huge oversimplification of the truthful finding that poor diet - low intake of wholegrains, oily fish, fruit and vegetables - is a leading contributor to disease.


To date, there have hardly been any randomised controlled trials (RCT; the type of study needed to make causal interpretations of research, e.g. so we can be sure that one thing causes another thing). Most of the noise around UPFs has come from one study done in just 20 people. To make matters worse this was an un-blinded trial, meaning that everyone knew which diet they were getting and so bias could have easily been introduced. Although over the two weeks those on the UPF diet ate on average 500kcal more and gained 0.9kg of body weight, energy intake at the end of the time period was going down, so the initial 'high' of eating such the UPF diet was fading. Also 50% of the weight gain and loss was found to be attributed to water weight, so when you think about the 0.45kg difference, it means almost nothing. Participants also rated the UPF diet just as palatable as the unprocessed diet, which suggests the opposite of what we're constantly told about these food which we're supposed to be so vulnerable to eating huge quantities of.


The rest of data on UPF is purely observational, which means we don't manipulate what people do we just look at their health and look for associations with what they report they eat. Typically, people are very bad at remembering what they eat accurately, so this type of study is only really useful for identifying potential trends which we can then explore further with RCT.


One recent review looked at the highest consumption of processed foods in various European countries and linked it with rates of obesity. This reported a general positive relationship between the two, with the UK having both the highest household availability of UPF (50.4% – although bear in mind that availability doesn’t necessarily indicate consumption or include foods eaten outside the home) and obesity (24.5%) of all countries in the study. However, there's a few reasons why observation studies like these should be taken with a grain of salt:


  1. Correlation doesn't necessarily imply causation. Particularly with the complex biological and environmental factors that determine our weight and the nature of our behaviours that influence food choice we cannot say that greater availability of UPF causes obesity.

  2. UPF have also been shown to be associated with things that there's no plausible reason that they should be associated with. In one study they were positively associated with accidental death, showing that if you look hard enough you can link pretty much anything with anything. Authors of this study suggest that "any causal estimate is likely smaller than we observed" or in other words there's likely more to this story than the standard line that UPF cause disease.

  3. Reverse causation should also be considered - instead of UPF causing diseases in those who consume the most of them, do these people with (often multiple) chronic conditions turn to UPF because they don't have the resources or capacity to eat more whole and minimally processed foods?


But why might they be harmful?

In his book Ultra-processed People Chris Van Tulleken states that “it is the ultra-processing, not the nutritional content, that’s the problem”. So if we're saying that it's not the nutritional content then he's basically arguing the difference is because of two things:

  • UPF are formulated to be more palatable and therefore we'll eat more of them

  • UPF contain food additives which might themselves be harmful to health


Food additives are added to foods for a huge range of reasons, e.g. to alter flavour, extend shelf-life, make a product hold together etc. They are also rigorously tested and the European Food Safety Authority are currently re-evaluating all the evidence on every additive approved before 2009 for safety. So far they have found no causes for concern for the way that they are currently used in the food industry.


As for the palatability argument this is not unique to UPF and includes many foods which contain fat and sugar which we are biologically programmed to have a greater liking for! As seen in the aforementioned RCT the non-processed diet was rated just as delicious as the UPF diet. So the argument doesn't necessarily hold up here either.


Duane Mellor, a dietitian and science communicator from Aston University put it like this when talking to Science Media Centre:


"There is also a potential issue by what is meant by ultra-processed foods, as the definition used can mean that ultra-processed foods can include many shop bought items such as a biscuit or potentially even a loaf of bread, are deemed worse than the near identical food made at home. The difference being time and cost, resulting in potential stigma, which is even more damaging at a time of a cost of living crisis, making people feel guilty about the food that they can afford and know their families will eat."


An alternative approach


The UK Scientific Advisory Committee on Nutrition (SACN) the body who create reports on nutrition and health for the UK Government to make policy and recommendations recently reviewed all the current evidence on UPF and concluded "the limitations in the NOVA classification system, the potential for confounding, and the possibility that the observed adverse associations with (ultra-) processed foods are covered by existing UK dietary recommendations mean that the evidence to date needs to be treated with caution."


In normal-speak this basically means that the NOVA system of classifying UPF is flawed, a lot of the research is weak and we currently already have dietary recommendations which help people understand what a 'healthy' diet is. Essentially what they're saying is that the use of the term and associated disdain is unhelpful at best and harmful at worst.


The use of the above NOVA definition doesn’t take into account the nutrient density of foods or the cost or the ease of preparing or eating the foods. In addition, many foods which we're actively encouraged to eat as they provide important nutrients, such as processed fruit and vegetables, bread, cheese and some breakfast cereals, fall into the category of UPF with no recognition of the reasons why we might eat them.


The hatred of all UPF also carries a certain level of snobbery to my mind and doesn’t take into account the huge inequalities we have in income and ability to prepare meals from scratch. And even when meals can be cooked from scratch this doesn't mean that one prepared at home to a recipe that's high in fat, salt and sugar is more nutritious than a supermarket version with fibre and protein but which happens to contain a couple of flavour enhancers or additives. The idea that foods cooked from scratch at home will always be more nutritionally sound than those found in supermarkets is just bullshit. Some research has shown that certain ready meals have more fibre and less saturated fat and would more often be given a green ‘traffic light’ label compared to recipes made from TV chefs' cook books.


We currently have no evidence which shows that it's UPF specifically that cause disease and yet many nutrition professionals, scientists and especially the media talk like there is undisputed evidence that they do. Cutting out UPF will not magically transform our health or make us a better person. Just to sum up I wanted to summarise why I believe UPF deserve defending:

  • They save us money – processed foods are often more shelf stable and therefore can be priced more cheaply

  • Nutrient content – arbitrarily categorising foods into unprocessed=good and processed=bad doesn’t take into account the nutrients contributed by the foods

  • They save us time - not everyone has the luxury of time, energy or resources to make every meal from scratch

  • They save on food waste - preserving foods means we can keep fresh produce for much longer than if we left them in their natural state

  • Processing makes foods safe to eat by reducing toxins and preventing growth of pathogenic or food spoilage microbes.


While I do think large food companies who are driven purely by profit margins and shareholders can do a better job, that's for Governments to sort out. We don't need to take all the individual burden on ourselves and it yet again distracts us from greater problems in our wider environment and makes us feel even more scared about the food we eat.


This is yet another example of reducing complex nutritional concerns into black and white categorisations, with the intention of improving health but only leading to elitism, confusion and incorrect messaging. Now I’m not saying we should eat ready meals everyday - cooking from scratch can be so rewarding for some, but definitely not everyone! - but shaming people for eating these kinds of foods due to lack of time, resources or ability is just wrong.


So next time you feel you ‘have to’ choose the £5 hand-baked crusty loaf over the 50p sliced bread, please just take a second to question why. That pause could save you a bundle of cash and make absolutely no difference to your long-term health!



Further reading:

Gibney et al. (2017). Ultra-processed foods in human health: a critical appraisal. Doi: 10.3945/ajcn.117.160440.

Monteiro et al. (2018). Household availability of ultra-processed foods and obesity in nineteen European countries. Doi: 10.1017/S1368980017001379

The Angry Chef (2016). An unfashionable defence of convenience. Available at: https://angry-chef.com/blog/an-unfashionable-defence-of-convenience


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