There was a little cafe I used to go to that did the best bacon sandwiches. They came in a soft and pillowy white bap. The bacon, thick-cut from a local butcher, was midway between crispy and chewy. Ketchup and HP sauce were served in miniature jars with the sandwich, so you could dab on the exact amount you liked. That was all there was to it: just bread and bacon and sauce. Eating one of these sandwiches, as I did every few weeks, with a cup of strong coffee, felt like an uncomplicated pleasure.

And then, all of a sudden, the bacon sandwich stopped being quite so comforting. For a few weeks in October 2015, half the people I knew were talking about the news that eating bacon was now a proven cause of cancer. You couldn’t miss the story: it was splashed large in every newspaper and all over the web. As one journalist wrote in Wired, “Perhaps no two words together are more likely to set the internet aflame than BACON and CANCER.” The BBC website announced, matter-of-factly, that “Processed meats do cause cancer”, while the Sun went with “Banger out of Order” and “Killer in the Kitchen”.

The source of the story was an announcement from the World Health Organization that “processed meats” were now classified as a group 1 carcinogen, meaning scientists were certain that there was “sufficient” evidence that they caused cancer, particularly colon cancer. The warning applied not just to British bacon but to Italian salami, Spanish chorizo, German bratwurst and myriad other foods.

Health scares are ten-a-penny, but this one was very hard to ignore. The WHO announcement came on advice from 22 cancer experts from 10 countries, who reviewed more than 400 studies on processed meat covering epidemiological data from hundreds of thousands of people. It was now possible to say that “eat less processed meat”, much like “eat more vegetables”, had become one of the very few absolutely incontrovertible pieces of evidence-based diet advice – not simply another high-profile nutrition fad. As every news report highlighted, processed meat was now in a group of 120 proven carcinogens, alongside alcohol, asbestos and tobacco – leading to a great many headlines blaring that bacon was as deadly as smoking.

The WHO advised that consuming 50g of processed meat a day – equivalent to just a couple of rashers of bacon or one hotdog – would raise the risk of getting bowel cancer by 18% over a lifetime. (Eating larger amounts raises your risk more.) Learning that your own risk of cancer has increased from something like 5% to something like 6% may not be frightening enough to put you off bacon sandwiches for ever. But learning that consumption of processed meat causes an additional 34,000 worldwide cancer deaths a year is much more chilling. According to Cancer Research UK, if no one ate processed or red meat in Britain, there would be 8,800 fewer cases of cancer. (That is four times the number of people killed annually on Britain’s roads.)

The news felt especially shocking because both ham and bacon are quintessentially British foods. Nearly a quarter of the adult population in Britain eats a ham sandwich for lunch on any given day, according to data from 2012 gathered by researchers Luke Yates and Alan Warde. To many consumers, bacon is not just a food; it is a repository of childhood memories, a totem of home. Surveys indicate that the smell of frying bacon is one of our favourite scents in the UK, along with cut grass and fresh bread. To be told that bacon had given millions of people cancer was a bit like finding out your granny had been secretly sprinkling arsenic on your morning toast.

Vegetarians might point out that the bacon sandwich should never have been seen as comforting. It is certainly no comfort for the pigs, most of whom are kept in squalid, cramped conditions. But for the rest of us, it was alarming to be told that these beloved foods might be contributing to thousands of needless human deaths. In the weeks following news of the WHO report, sales of bacon and sausages fell dramatically. British supermarkets reported a £3m drop in sales in just a fortnight. (“It was very detrimental,” said Kirsty Adams, the product developer for meat at Marks and Spencer.)

But just when it looked as if this may be #Bacongeddon (one of many agonised bacon-related hashtags trending in October 2015), a second wave of stories flooded in. Their message was: panic over. For one thing, the analogy between bacon and smoking was misleading. Smoking tobacco and eating processed meat are both dangerous, but not on the same scale. To put it in context, around 86% of lung cancers are linked to smoking, whereas it seems that just 21% of bowel cancers can be attributed to eating processed or red meat. A few weeks after publishing the report, the WHO issued a clarification insisting it was not telling consumers to stop eating processed meat.

Meanwhile, the meat industry was busily insisting that there was nothing to see here. The North American Meat Institute, an industry lobby group, called the report “dramatic and alarmist overreach”. A whole tranche of articles insisted in a commonsense tone that it would be premature and foolish to ditch our meaty fry-ups just because of a little cancer scare.

Nearly three years on, it feels like business as usual for processed meats. Many of us seem to have got over our initial sense of alarm. Sales of bacon in the UK are buoyant, having risen 5% in the two years up to mid-2016. When I interviewed a product developer for Sainsbury’s supermarket last year, she said that one of the quickest ways to get British consumers to try a new product now was to add chorizo to it.

And yet the evidence linking bacon to cancer is stronger than ever. In January, a new large-scale study using data from 262,195 British women suggested that consuming just 9g of bacon a day – less than a rasher – could significantly raise the risk of developing breast cancer later in life. The study’s lead author, Jill Pell from the Institute of Health and Wellbeing at Glasgow University, told me that while it can be counterproductive to push for total abstinence, the scientific evidence suggests “it would be misleading” for health authorities to set any safe dose for processed meat “other than zero”.

The real scandal of bacon, however, is that it didn’t have to be anything like so damaging to our health. The part of the story we haven’t been told – including by the WHO – is that there were always other ways to manufacture these products that would make them significantly less carcinogenic. The fact that this is so little known is tribute to the power of the meat industry, which has for the past 40 years been engaged in a campaign of cover-ups and misdirection to rival the dirty tricks of Big Tobacco.

How do you choose a pack of bacon in a shop, assuming you are a meat eater? First, you opt for either the crispy fat of streaky or the leanness of back. Then you decide between smoked or unsmoked – each version has its passionate defenders (I am of the unsmoked persuasion). Maybe you seek out a packet made from free-range or organic meat, or maybe your budget is squeezed and you search for any bacon on special offer. Either way, before you put the pack in your basket, you have one last look, to check if the meat is pink enough.

Since we eat with our eyes, the main way we judge the quality of cured meats is pinkness. Yet it is this very colour that we should be suspicious of, as the French journalist Guillaume Coudray explains in a book published in France last year called Cochonneries, a word that means both “piggeries” and “rubbish” or “junk food”. The subtitle is “How Charcuterie Became a Poison”. Cochonneries reads like a crime novel, in which the processed meat industry is the perpetrator and ordinary consumers are the victims.

The pinkness of bacon – or cooked ham, or salami – is a sign that it has been treated with chemicals, more specifically with nitrates and nitrites. It is the use of these chemicals that is widely believed to be the reason why “processed meat” is much more carcinogenic than unprocessed meat. Coudray argues that we should speak not of “processed meat” but “nitro-meat”.

Prosciutto di Parma has been produced without nitrates since 1993. Photograph: Stefano Rellandini/Reuters

“Pure insane crazy madness” is how Coudray described the continuing use of nitrates and nitrites in processed meats, in an email to me. The madness, in his view, is that it is possible to make bacon and ham in ways that would be less carcinogenic. The most basic way to cure any meat is to salt it – either with a dry salt rub or a wet brine – and to wait for time to do the rest. Coudray notes that ham and bacon manufacturers claim this old-fashioned way of curing isn’t safe. But the real reason they reject it is cost: it takes much longer for processed meats to develop their flavour this way, which cuts into profits.

There is much confusion about what “processed meat” actually means, a confusion encouraged by the bacon industry, which benefits from us thinking there is no difference between a freshly minced lamb kofta and a pizza smothered in nitrate-cured pepperoni. Technically, processed meat means pork or beef that has been salted and cured, with or without smoking. A fresh pound of beef mince isn’t processed. A hard stick of cured salami is.

The health risk of bacon is largely to do with two food additives: potassium nitrate (also known as saltpetre) and sodium nitrite. It is these that give salamis, bacons and cooked hams their alluring pink colour. Saltpetre – sometimes called sal prunella – has been used in some recipes for salted meats since ancient times. As Jane Grigson explains in Charcuterie and French Pork Cookery, saltpetre was traditionally used when brining hams to give them “an attractive rosy appearance when otherwise it would be a murky greyish brown”.

In earlier centuries, bacon-makers who used saltpetre did not understand that it converts to nitrite as the meat cures. It is this nitrite that allows the bacteria responsible for cured flavour to emerge quicker, by inhibiting the growth of other bacteria. But in the early 20th century, the meat industry found that the production of cured meats could be streamlined by adding sodium nitrite to the pork in pure form. In trade journals of the 1960s, the firms who sold nitrite powders to ham-makers spoke quite openly about how the main advantage was to increase profit margins by speeding up production. One French brand of sodium nitrite from the 60s was called Vitorose or “quick-pink”.

Nitro-chemicals have been less of a boon to consumers. In and of themselves, these chemicals are not carcinogenic. After all, nitrate is naturally present in many green vegetables, including celery and spinach, something that bacon manufacturers often jubilantly point out. As one British bacon-maker told me, “There’s nitrate in lettuce and no one is telling us not to eat that!”

But something different happens when nitrates are used in meat processing. When nitrates interact with certain components in red meat (haem iron, amines and amides), they form N-nitroso compounds, which cause cancer. The best known of these compounds is nitrosamine. This, as Guillaume Coudray explained to me in an email, is known to be “carcinogenic even at a very low dose”. Any time someone eats bacon, ham or other processed meat, their gut receives a dose of nitrosamines, which damage the cells in the lining of the bowel, and can lead to cancer.

You would not know it from the way bacon is sold, but scientists have known nitrosamines are carcinogenic for a very long time. More than 60 years ago, in 1956, two British researchers called Peter Magee and John Barnes found that when rats were fed dimethyl nitrosamine, they developed malignant liver tumours. By the 1970s, animal studies showed that small, repeated doses of nitrosamines and nitrosamides – exactly the kind of regular dose a person might have when eating a daily breakfast of bacon – were found to cause tumours in many organs including the liver, stomach, oesophagus, intestines, bladder, brain, lungs and kidneys.

Just because something is a carcinogen in rats and other mammals does not mean it will cause cancer in humans, but as far back as 1976, cancer scientist William Lijinsky argued that “we must assume” that these N-nitroso compounds found in meats such as bacon were also “carcinogens for man”. In the years since, researchers have gathered a massive body of evidence to lend weight to that assumption. In 1994, to take just one paper among hundreds on nitrosamines and cancer, two American epidemiologists found that eating hotdogs one or more times a week was associated with higher rates of childhood brain cancer, particularly for children who also had few vitamins in their diets.

In 1993, Parma ham producers in Italy made a collective decision to remove nitrates from their products and revert to using only salt, as in the old days. For the past 25 years, no nitrates or nitrites have been used in any Prosciutto di Parma. Even without nitrate or nitrite, the Parma ham stays a deep rosy-pink colour. We now know that the colour in Parma ham is totally harmless, a result of the enzyme reactions during the ham’s 18-month ageing process.

Slow-cured, nitrate-free, artisan hams are one thing, but what about mass-market meats? Eighteen months would be “a long time to wait on hotdogs”, as the food science expert Harold McGee comments. But there have always been recipes for nitrate-free bacon using nothing but salt and herbs. John Gower of Quiet Waters Farm, a pork producer who advises many British manufacturers of cured meats, confirms that nitrate is not a necessary ingredient in bacon: “It’s generally accepted that solid muscle products, as opposed to chopped meat products like salami, don’t require the addition of nitrate for safety reasons.”

Bacon is proof, if it were needed, that we cling to old comforts long after they have been proven harmful. The attachment of producers to nitrates in bacon is mostly “cultural”, says Gower. Bacon cured by traditional methods without nitrates and nitrites will lack what Gower calls that “hard-to-define tang, that delicious almost metallic taste” that makes bacon taste of bacon to British consumers. Bacon without nitrates, says Gower, is nothing but “salt pork”.

Given the harm of “nitro-meat” has been known for so long, the obvious question is why more has not been done to protect us from it. Corinna Hawkes, a professor of Food Policy at City University in London, has been predicting for years that processed meats will be “the next sugar” – a food so harmful that there will be demands for government agencies to step in and protect us. Some day soon, Hawkes believes, consumers will finally wake up to the clear links between cancer and processed meat and say “Why didn’t someone tell me about this?”

The most amazing thing about the bacon panic of 2015 was that it took so long for official public health advice to turn against processed meat. It could have happened 40 years earlier. The only time that the processed meat industry has looked seriously vulnerable was during the 1970s, a decade that saw the so-called “war on nitrates” in the US. In an era of Ralph Nader-style consumer activism, there was a gathering mood in favour of protecting shoppers against bacon – which one prominent public health scientist called “the most dangerous food in the supermarket”. In 1973, Leo Freedman, the chief toxicologist of the US Food and Drug Administration, confirmed to the New York Times that “nitrosamines are a carcinogen for humans” although he also mentioned that he liked bacon “as well as anybody”.

The US meat industry realised it had to act fast to protect bacon against the cancer charge. The first attempts to fight back were simply to ridicule the scientists for over-reacting. In a 1975 article titled “Factual look at bacon scare”, Farmers Weekly insisted that a medium-weight man would have to consume more than 11 tonnes of bacon every single day to run the faintest risk of cancer. This was an outrageous fabrication.

But soon the meat lobby came up with a cleverer form of diversion. The AMI – the American Meat Institute – started to make the argument that the nitrate was only there for the consumer’s own safety, to ward off botulism – a potentially fatal toxin sometimes produced by poorly preserved foods. The scientific director of the AMI argued that a single cup of botulism would be enough to wipe out every human on the planet. So, far from harming lives, bacon was actually saving them.

In 1977, the FDA and the US Department of Agriculture gave the meat industry three months to prove that nitrate and nitrite in bacon caused no harm. “Without a satisfactory response,” Coudray writes, “these additives would have to be replaced 36 months later with non-carcinogenic methods.” The meat industry could not prove that nitrosamines were not carcinogenic – because it was already known that they were. Instead, the argument was made that nitrates and nitrites were utterly essential for the making of bacon, because without them bacon would cause thousands of deaths from botulism. In 1978, in response to the FDA’s challenge, Richard Lyng, director of the AMI, argued that nitrites are to processed meat “as yeast is to bread”.

The meat industry’s tactics in defending bacon have been “right out of the tobacco industry’s playbook”, according to Marion Nestle, professor of nutrition and food studies at New York University. The first move is: attack the science. By the 1980s, the AMI was financing a group of scientists based at the University of Wisconsin. These meat researchers published a stream of articles casting doubt on the harmfulness of nitrates and exaggerating the risk from botulism of non-nitrated hams.

Does making ham without nitrite lead to botulism? If so, it is a little strange that in the 25 years that Parma ham has been made without nitrites, there has not been a single case of botulism associated with it. Almost all the cases of botulism from preserved food – which are extremely rare – have been the result of imperfectly preserved vegetables, such as bottled green beans, peas and mushrooms. The botulism argument was a smokescreen. The more that consumers could be made to feel that the harmfulness of nitrate and nitrite in bacon and ham was still a matter of debate, the more they could be encouraged to calm down and keep buying bacon.

A bacon sandwich at a diner in Michigan. Photograph: Molly Riley/Reuters

The botulism pretext was very effective. The AMI managed to get the FDA to keep delaying its three-month ultimatum on nitrites until a new FDA commissioner was appointed in 1980 – one more sympathetic to hotdogs. The nitrite ban was shelved. The only concession the industry had made was to limit the percentage of nitrites added to processed meat and to agree to add vitamin C, which would supposedly mitigate the formation of nitrosamines, although it does nothing to prevent the formation of another known carcinogen, nitrosyl-haem.

Over the years, the messages challenging the dangers of bacon have become ever more outlandish. An explainer article by the Meat Science and Muscle Biology lab at the University of Wisconsin argues that sodium nitrite is in fact “critical for maintaining human health by controlling blood pressure, preventing memory loss, and accelerating wound healing”. A French meat industry website, info-nitrites.fr, argues that the use of the “right dose” of nitrites in ham guarantees “healthy and safe” products, and insists that ham is an excellent food for children.

The bacon lobby has also found surprising allies among the natural foods brigade. Type “nitrate cancer bacon” into Google, and you will find a number of healthy eating articles, some of them written by advocates of the “Paleo” diet, arguing that bacon is actually a much-maligned health food. The writers often mention that vegetables are the primary source of nitrates, and that human saliva is high in nitrite. One widely shared article claims that giving up bacon would be as absurd as attempting to stop swallowing. Out of the mass of stuff on the internet defending the healthiness of bacon, it can be hard to tell which writers have fallen under the sway of the meat lobby, and which are simply clueless “nutrition experts” who don’t know any better.

Either way, this misinformation has the potential to make thousands of people unwell. The mystifying part is why the rest of us have been so willing to accept the cover-up.

Our deepening knowledge of its harm has done very little to damage the comforting cultural associations of bacon. While I was researching this article, I felt a rising disgust at the repeated dishonesty of the processed meat industry. I thought about hospital wards and the horrible pain and indignity of bowel cancer. But then I remembered being in the kitchen with my father as a child on a Sunday morning, watching him fry bacon. When all the bacon was cooked, he would take a few squares of bread and fry them in the meaty fat until they had soaked up all its goodness.

In theory, our habit of eating salted and cured meats should have died out as soon as home refrigerators became widespread in the mid-20th century. But tastes in food are seldom rational, and millions of us are still hooked on the salty, smoky, umami savour of sizzling bacon.

We are sentimental about bacon in a way we never were with cigarettes, and this stops us from thinking straight. The widespread willingness to forgive pink, nitrated bacon for causing cancer illustrates how torn we feel when something beloved in our culture is proven to be detrimental to health. Our brains can’t cope with the horrid feeling that bacon is not what we thought it was, and so we turn our anger outwards to the health gurus warning us of its hazards. The reaction of many consumers to the WHO report of 2015 was: hands off my bacon!

In 2010, the EU considered banning the use of nitrates in organic meats. Perhaps surprisingly, the British organic bacon industry vigorously opposed the proposed nitrates ban. Richard Jacobs, the late chief executive of Organic Farmers & Growers, an industry body, said that prohibiting nitrate and nitrite would have meant the “collapse” of a growing market for organic bacon.

Organic bacon produced with nitrates sounds like a contradiction in terms, given that most consumers of organic food buy it out of concerns for food safety. Having gone to the trouble of rearing pigs using free-range methods and giving them only organic feed, why would you then cure the meat in ways that make it carcinogenic? In Denmark, all organic bacon is nitrate-free. But the UK organic industry insisted that British shoppers would be unlikely to accept bacon that was ‘“greyish”.

Then again, the slowness of consumers to lose our faith in pink bacon may partly be a response to the confusing way that the health message has been communicated to us. When it comes to processed meat, we have been misled not just by wild exaggerations of the food industry but by the caution of science.

On the WHO website, the harmfulness of nitrite-treated meats is explained so opaquely you could miss it altogether. In the middle of a paragraph on “what makes red meat and processed meat increase the risk of cancer”, it says: “For instance, carcinogenic chemicals that form during meat processing include N-nitroso compounds.” What this means, in plain English, is that nitrites make bacon more carcinogenic. But instead of spelling this out, the WHO moves swiftly on to the question of how both red and processed meats might cause cancer, after adding that “it is not yet fully understood how cancer risk is increased”.

The typical British sausage does not fall into the ‘processed meat’ category. Photograph: Julian Smith/AAP

This caution has kept us as consumers unnecessarily in the dark. Consider sausages. For years, I believed that the unhealthiest part in a cooked English breakfast was the sausage, rather than the bacon. Before I started to research this article, I’d have sworn that sausages fell squarely into the “processed meat” category. They are wrongly listed as such on the NHS website.

But the average British sausage – as opposed to a hard sausage like a French saucisson – is not cured, being made of nothing but fresh meat, breadcrumbs, herbs, salt and E223, a preservative that is non-carcinogenic. After much questioning, two expert spokespeople for the US National Cancer Institute confirmed to me that “one might consider” fresh sausages to be “red meat” and not processed meat, and thus only a “probable” carcinogen. (To me, the fact that most sausages are not processed meat was deeply cheering, and set me dancing around the kitchen with glee thinking about toad in the hole.)

In general, if you ask a cancer scientist to distinguish between the risks of eating different types of meat, they become understandably cagey. The two experts at the National Cancer Institute told me that meats containing nitrites and nitrates have “consistently been associated with increased risk of colon cancer” in human studies. But they added that “it is difficult to separate nitrosamines from other possible carcinogens that may be present in processed meats like bacon”. These other suspects include haem iron – a substance that is abundant in all red meat, processed or not – and heterocyclic amines: chemicals that form in meat during cooking. A piece of crispy, overcooked bacon will contain multiple carcinogens, and not all are due to the nitrates.

The problem with this reasoning, as I see it, is that it can’t account for why processed meat is so much more closely linked to cancer than cooked red meat. For that, there remains no plausible explanation except for nitrates and nitrites. But looking for clear confirmation of this in the data is tricky, given that humans do not eat in labs under clinical observation.

Most of what we know about processed meat and cancer in humans comes from epidemiology – the study of disease across whole populations. But epidemiologists do not ask the kind of detailed questions about food that the people who eat that food may like answers to. The epidemiological data – based on surveys of what people eat – is now devastatingly clear that diets high in “processed meats” lead to a higher incidence of cancer. But it can’t tell us how or why or which meats are the best or worst. As Corinna Hawkes of City University comments, “The researchers don’t ask you if you are eating artisanal charcuterie from the local Italian deli or the cheapest hotdogs on the planet.”

I would love to see data comparing the cancer risk of eating nitrate-free Parma ham with that of traditional bacon, but no epidemiologist has yet done such a study. The closest anyone has come was a French study from 2015, which found that consumption of nitrosylated haem iron – as found in processed meats – had a more direct association with colon cancer than the haem iron that is present in fresh red meat.

It may be possible that epidemiologists have not asked people more detailed questions about what kind of processed meats they eat because they assume there is no mass-market alternative to bacon made without nitrates or nitrites. But this is about to change.

The technology now exists to make the pink meats we love in a less damaging form, which raises the question of why the old kind is still so freely sold. Ever since the “war on nitrates” of the 1970s, US consumers have been more savvy about nitrates than those in Europe, and there is a lot of “nitrate-free bacon” on the market. The trouble, as Jill Pell remarks, is that most of the bacon labelled as nitrate-free in the US “isn’t nitrate-free”. It’s made with nitrates taken from celery extract, which may be natural, but produces exactly the same N-nitroso compounds in the meat. Under EU regulation, this bacon would not be allowed to be labelled “nitrate-free”.

“It’s the worst con I’ve ever seen in my entire life,” says Denis Lynn, the chair of Finnebrogue Artisan, a Northern Irish company that makes sausages for many UK supermarkets, including Marks & Spencer. For years, Lynn had been hoping to diversify into bacon and ham but, he says, “I wasn’t going to do it until we found a way to do it without nitrates.”

When Lynn heard about a new process, developed in Spain, for making perfectly pink, nitrate-free bacon, he assumed it was another blind alley. In 2009, Juan de Dios Hernandez Canovas, a food scientist and the head of the food tech company Prosur, found that if he added certain fruit extracts to fresh pork, it stayed pink for a surprisingly long time.

In January 2018, Finnebrogue used this technology to launch genuinely nitrate-free bacon and ham in the UK. It is sold in Sainsbury’s and Waitrose as “Naked Bacon” and “Naked Ham”, and in M&S as “made without nitrites”. Kirsty Adams, who oversaw its launch at M&S, explains that “it’s not really cured”. It’s more like a fresh salted pork injected with a fruit and vegetable extract, and is more perishable than an old-fashioned flitch of bacon – but that doesn’t matter, given that it is kept in a fridge. Because it is quick to produce, this is much more “economically viable” to make than some of the other nitrate-free options, such as slow-cured Parma ham. The bacon currently sells in Waitrose for £3 a pack, which is not the cheapest, but not prohibitive either.

I tried some of the Finnebrogue bacon from M&S. The back bacon tasted pleasant and mild, with a slight fruitiness. It didn’t have the toothsome texture or smoky depth of a rasher of butcher’s dry-cured bacon, but I’d happily buy it again as an alternative to “nitro-meat”. None of my family noticed the difference in a spaghetti amatriciana.

Nitrite-free bacon still sounds a bit fancy and niche, but there shouldn’t be anything niche about the desire to eat food that doesn’t raise your risk of cancer. Lynn says that when he first approached Prosur about the fruit extract, he asked how much they had sold to the other big bacon manufacturers during the two years they had been offering it in the UK. The answer was none. “None of the big guys wanted to take it,” claims Lynn. “They said: ‘It will make our other processed meats look dodgy’”.

But it also remains to be seen how much consumer demand there will be for nitrite- or nitrate-free bacon. For all the noise about bacon and cancer, it isn’t easy to disentangle at a personal level just what kind of risk we are at when we eat a bacon sandwich. OK, so 34,000 people may die each year because of processed meat in their diet, but the odds are that it won’t be you. I asked a series of cancer scientists whether they personally ate processed meat, and they all gave slightly different answers. Jill Pell said she was mostly vegetarian and ate processed meats very rarely. But when I asked Fabrice Pierre, a French expert on colon cancer and meat, if he eats ham, he replied: “Yes, of course. But with vegetables at the same meal.” (Pierre’s research at the Toxalim lab has shown him that some of the carcinogenic effects of ham can be offset by eating vegetables.)

Our endless doubt and confusion about what we should be eating have been a gift to the bacon industry. The cover-up about the harm of meat cured with nitrates and nitrites has been helped along by the scepticism many of us feel about all diet advice. At the height of the great bacon scare of 2015, lots of intelligent voices were saying that it was safe to ignore the new classification of processed meats as carcinogenic, because you can’t trust anything these nutritionists say. Meanwhile, millions of consumers of ham and bacon, many of them children, are left unprotected. Perhaps the most extraordinary thing about this controversy is how little public outrage it has generated. Despite everything, most of us still treat bacon as a dear old friend.

In an ideal world, we would all be eating diets lower in meat, processed or otherwise, for the sake of sustainability and animal welfare as much as health. But in the world we actually live in, processed meats are still a normal, staple protein for millions of people who can’t afford to swap a value pack of frying bacon for a few slivers of Prosciutto di Parma. Around half of all meat eaten in developed countries is now processed, according to researcher John Kearney, making it a far more universal habit than smoking.

The real victims in all this are not people like me who enjoy the occasional bacon-on-sourdough in a hipster cafe. The people who will be worst affected are those – many on low incomes – for whom the cancer risk from bacon is compounded by other risk factors such as eating low-fibre diets with few vegetables or wholegrains. In his book, Coudray points out that in coming years, millions more poor consumers will be affected by preventable colon cancer, as westernised processed meats conquer the developing world.

Last month, Michele Rivasi, a French MEP, launched a campaign – in collaboration with Coudray – demanding a ban of nitrites from all meat products across Europe. Given how vigorously the bacon industry has fought its corner thus far, a total ban on nitrites looks unlikely.

But there are other things that could be done about the risk of nitrites and nitrates in bacon, short of an absolute veto. Better information would be a start. As Corinna Hawkes points out, it is “surprising” that there hasn’t been more of an effort from government to inform people about the risks of eating ham and bacon, perhaps through warning labels on processed meats. But where is the British politician brave enough to cast doubt on bacon?

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