Ultra-processed foods: reflections on what we know and what is coming

Coming into my new role as Interim Head of Policy and Public Affairs ¹ at World Cancer Research Fund (WCRF) International, I was immediately faced with trying to understand what ultra-processed foods (UPFs) are and how they might, or might not, contribute to cancer risk.

The harms caused by UPFs have been a growing concern in public health, cancer research and nutrition policy over recent years. The increasing number of scientific publications such as Kevin Hall’s 2019 research and the recent Lancet series on UPFs and human health have further amplified and elevated attention to this critical issue. However, to be certain of the risks between UPFs and cancer, there is a need to identify, review and judge the strength of the evidence related to these potential links.

Foods can go through many different types of processing, not all of which are unhealthy. From common practices such as baking homemade bread and pasteurising milk, to commercial and industrial production which breaks foods down and recombines them, often using artificial preservatives and ingredients that aren’t normally found in a kitchen.

In 2010, the NOVA system of food classification was introduced and is now a common tool to categorise foods according to their level of processing:

• Unprocessed and minimally processed foods, containing no added fats, salt, sugar or other additives. Examples include frozen fruit and vegetables, and pasteurised milk.
• Processed culinary ingredients. These are ingredients that aren’t created to be eaten alone and are often used alongside foods in group 1 such as oils, sugars and salt.
• Processed food, where a product from group 2 – like salt, sugar, fat or vinegar – is added to minimally-processed foods. Examples include tinned goods such as lentils and beans, salted nuts and cheese.
• Ultra-processed foods. Many of the foods we consume daily fall into this category: pre-packaged meals (and yes, I have to admit, I am partial to an easy-to-cook ready meal on a Friday night), industrialised bread, sweets, soft drinks and sweetened yoghurt.

Why is this important and what does it mean for health?

Across the world, the average share of UPFs in a person’s diet ranges from 9% in Iran to 60% in the USA². Recent UK data shows that 57% of the calories British people eat come from UPFs: a figure that rises, worryingly, to 63.5% for children aged 1.5-11 years and 68% for adolescents aged between 12-18 years. Furthermore, there are critical health equity dimensions to the consumption of UPFs, with greater exposure to UPFs often being found among lower-income, marginalised or socially disadvantaged populations.

The increasing consumption of UPFs is a trend that is being seen not just in high-income countries, but also in low- and middle-income countries (LMICs), leading to a double burden of malnutrition, with many LMICs being faced with challenges of both undernutrition and overweight and obesity at the same time³.

Alongside the growing body of evidence suggesting that UPFs are harmful to health, these trends are concerning. Combining the steady increase of UPF production and consumption in both high-income and lower-income countries, the way in which producers of UPFs undermine food systems and dietary patterns (by displacing minimally processed foods and being more affordable than freshly prepared meals), and the impact of UPFs on pollution, greenhouse gas emissions and biodiversity loss, it is abundantly clear that the growing consumption of UPFs requires urgent policy action.

But what is the link between UPFs and cancer?

Well, the honest answer is that, at the moment, we are not entirely sure. The recent Lancet review of available evidence found some indications that an ultra-processed dietary pattern increased risk of a range of chronic diseases, including cancer-related morbidity and mortality. A small number of studies found an association between the consumption of UPFs and increased overall incidence of cancer.

However, to be certain of the risks between UPFs and cancer, there is a need to identify, review and judge the strength of the evidence related to the potential links between UPFs and cancer risk. This includes the evidence related to the biological mechanisms that may be driving these links. It may also be the case that UPFs, in and of themselves, do not increase our risk of cancer directly but increase the risk of things we know do. For example, the Lancet study found a clear association between UPFs and overweight or obesity – and we know that people living with overweight or obesity have an increased risk of at least 13 different types of cancer. We also know that one way to prevent cancer is to avoid processed meat as we highlight in our 10 Cancer Prevention Recommendations.

What have I learned so far?

In my second week in my new role, I was fortunate enough to attend a policy forum on UPFs organised by Imperial College London. The forum set out a clear case for action and highlighted some excellent examples of good practice in national policy implementation to reduce consumption of UPFs. Two things struck me during this forum:

• The scale of the challenge we are facing: from the force of social media algorithms that dramatically increase exposure to UPF marketing practices, to the power large industry holds over food production and manufacturing processes, and the challenges of implementing regulatory policies that tackle rather than exacerbate health inequities.
• That we can do something about it: the UPF Policy Forum also highlighted progress being made to emphasise the contents of food to consumers (such as high amounts of sugar, salt or fat) using front-of-packing labels. These advances, as demonstrated in the Americas, are a WHO Best Buy policy that can improve consumers’ understanding and choices of foods they eat, as well as push food producers to improve the quality of foods they are making.

My third observation, or question, coming out of the UPF Policy Forum, however, was ‘what does this mean for me in my new role at WCRF International?’ I can see that there are some linkages between UPFs and cancer, but these are in no way conclusive. How can I legitimately argue that by reducing consumption of UPFs you can reduce your risk of cancer when there are still so many unanswered questions? And how can I advocate for policy change without robust scientific evidence?

The good news is that this evidence is coming

WCRF International’s Global Cancer Update Programme, CUP Global, has this year included a systematic review of evidence on UPFs and cancer risk. While there is no guarantee that this review will lead to a clear conclusion on the linkages between UPFs and cancer, it will certainly add more evidence to help inform the debate.

With that in mind, I’m looking forward to July when our CUP Global Expert Panel will come together and review the latest evidence on this. So, if you want to keep informed on the links between UPFs and cancer risk, keep watching this space. Or even better, follow us on LinkedIn and sign up to our monthly e-news for the latest updates.

Notes and references:

¹ I’ll be covering this role while Kate Oldridge-Turner is on maternity leave.

² Monteiro C, Louzada M, Steele-Martinez E et al. Ultra-processed foods and human health: the main thesis and evidence. The Lancet, 2025; 406, 266702684.

³ Popkin B, Corvalan C, Grummer-Strawn L Dynamics of the double burden of malnutrition and the changing nutrition reality. The Lancet, 2019; 395, 65-74.