Don’t Go Bacon My Heart: What do we mean when we talk about processed meat?

By Dr Anika Knuppel and Dr Keren Papier


Don’t go bacon my heart was an online survey about what people know and found surprising about processed meat by Dr Keren Papier and Dr Anika Knüppel of the Cancer Epidemiology Unit and the Livestock, Environment and People (LEAP) programme.

Processed meat and health

After an extensive review of the scientific literature in 2015, the World Health Organisation (WHO) defined processed meat as carcinogenic [having the potential to cause cancer] to humans and red meat as probably carcinogenic to humans and has continuously found these meats, and in particular processed meat, to be associated with an increased risk of colorectal cancer. These findings have led many countries (including the UK) to set recommendations to reduce red and processed meat consumption. Public Health England (PHE) currently recommends ‘On average eat no more than 70g of red and processed meat a day’, a recommendation that is still exceeded by men in the UK.

Why does this matter?

The risk of colorectal cancer has been shown to increase by 35% and 12% with every 100 grams higher intake of processed meat and unprocessed red meat, respectively and colorectal cancer is the 3rd most common cancer worldwide. So it is especially important that we can correctly identify processed meat in order to help reduce our risk.

But what exactly are we talking about when we talk about processed meat? And do researchers and the public understand the same things from this term?

But what exactly is processed meat? The Oxford dictionary describes processed as subjected to or treated by a special process; esp. (of food) preserved by processing which would apply to nearly all meat; except for Carpaccio, most meat at least undergoes the process of cooking. As one of our survey participants pointed out “It seems intuitive that changing the shape of meat (mincing it, putting that into burger / sausage etc. shape) would constitute 'processing'”. But according to the WHO, processed meat refers to meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavour or improve preservation, an often cited example is bacon. So already the common definition is not the same as the one used in health research. It might be too late to coin another term for processed meat, but it might not be too late to improve our communication in the future. While there are some prime examples of processed meat such as bacon, some foods harder to categorise – mince is unprocessed, hamburgers are processed, but what about homemade hamburgers?

Don’t Go Bacon my Heart

To find out more about how the WHO definition of processed meat is understood, we designed a Covid-safe public engagement activity called ‘Don’t Go Bacon my Heart’. Our online survey ran for one month and reached 335 people from around the world. The aims of our survey were simple: 1) we wanted to see if the public understood what processed meat was, and 2) whether ‘context’ (how or where meat was purchased or consumed) affected this understanding. To answer these, our survey displayed photos of 16 types of meat and asked participants to select which of these were ‘unprocessed’ or ‘processed’ (see Figure 1). We then gave participants the WHO definition of processed meat and checked how they classified meat products depending on where they were purchased or consumed. We also added a short video at the end of the activity to offer some clarification on the definition of processed meat (see Media 1).



Labelling processed meat

Our survey showed that the responders generally understood which meat was considered processed meat, with >90% of participants classifying 10/16 foods as processed or unprocessed meat correctly (see Figure 2). But we noticed that there was some confusion around some meat types, minced meat and lamb curry in particular.

Figure 2 Percent correctly classified by meat type by the respondents of Don’t Go Bacon my Heart. Black bars show-processed, white bars unprocessed meat.


Adding context

We found that context does confuse people. Our survey revealed that some of the confusion was related to ethnicity and country of residence – with participants from outside the UK and those of non-white ethnicity being at a disadvantage. But do these differences reflect a misunderstanding or real differences in the type of meat being consumed in these groups? For example, participants from outside of the UK (20% vs 12%) and those of non-white ethnicity (23% vs 13%) were more likely to classify kebab as unprocessed meat, which the WHO defines as processed meat based on industrial level mixing and processing. It is possible that kebab meat might be prepared and consumed differently in these different settings (i.e. home processing and therefore not processed meat). These findings highlight that the context may affect both how processed meat is classified, especially when it comes to local food internationally.

When comparing our findings by how often respondents ate meat, responders with higher meat intake were more likely to know the ins and outs of processed vs. unprocessed meat. For example of those eating meat at least two times per week 64% knew that minced meat was considered unprocessed compared to 47% of those eating meat max once per week. Similarly they correctly identified that homemade burgers were unprocessed (72% vs 28%).This suggests that the understanding of processed meat depends on meat intake.

When asking whether pork or poultry bacon could be considered processed meat we found that those in academia knew that both were processed meat (78%) while non-academics thought poultry bacon might be considered unprocessed meat (61%). This finding suggests that when talking about processed meat we need to highlight that all meat types could be made into processed meat, especially when talking to different demographics.

Defining processed meat in research – why scientists rely on composite terms such as processed meat?

In an ideal world, we would like science to be able to identify the culprits of the carcinogenic effects of processed meat more clearly, to clarify this question once and for all. From a scientific perspective, there are different types of processing that carry different risks and relate to different carcinogenic pathways.

When investigating associations between meat intake and future cancer risk, participants are drawn from the general population. This means researchers depend on the actual intake of people, and most do not just eat one type of meat, making it difficult to distinguish risks. In a study in half a million adults in the UK, we found that 44 % of those in the highest intake group of red unprocessed meat (>= 4 times/week) were also in the highest intake group of processed meat (>=2 times/week). This makes it unlikely that we could compare steak eaters to bacon eaters. How people eat is unlikely to change, still, future studies could improve the way questions on processed meat are asked.

So what?

With ‘Don’t Go Bacon my Heart’ we learned that most people generally have a good understanding of what processed meat is, but that nutrition researchers like us can improve how we communicate research on processed meat by considering 1) how some foods are consumed in different settings and cultures, 2) how often people eat meat and 3) the audience’s demographic.

Media 1 Video part of Don’t Go Bacon my Heart ‘Processed meat - does context matter? A short interview.’