Most of what we eat is ‘processed’ food. Here’s why we should be worried

Don’t panic, but each time you eat a bacon sandwich it is estimated you reduce your life by half an hour. We used to think that was due to the high fat content but the evidence now suggests it is to do with how bacon is made.

Definitions of processed food vary depending on your viewpoint. Everyone agrees that a tub of pot noodles, instant ramen or most ready meals that students ‘nuke’ in the microwave are highly processed. Other foods like frozen lasagne or pizza, chicken nuggets, cakes, biscuits, corn snacks, margarine, processed cheese, spaghetti sauces and ketchup are also now generally recognised as processed.

But what about other common foods? How about white pasta made from highly refined grains? We know that for a food to be healthy it needs to be as unrefined as possible and when it comes to rice and pasta this means brown or wholegrain because these varieties include more fibre and nutrients. (When polished rice was first produced there was an epidemic of a vitamin B deficiency called beriberi — a clear example of the health hazards caused by processing.)

But how do we sort the good from the bad?

Processed food is usually defined as food prepared with chemical additives or that has undergone processes to alter its flavour or shelf life. At its most extreme it can be called any food with something added to it that doesn’t occur in nature. Many products you may not have thought about are processed. Bagged salads in supermarkets usually contain some preservatives and chemicals from the washing process and packaging and so are all to some extent processed.

Natural ‘Greek-style’ yoghurt, as opposed to natural Greek yoghurt, is cleverly processed, using a variety of shortcuts, milk powders and starches to replace real milk and flavour in order to simplify manufacture. These don’t appear on the label.

Most of our bread is also highly processed and contains chemicals and preservatives and colourants to make it look brown and wholesome.

The WHO outraged many European citizens when they labelled many countries’ favourite foods — from bacon to Wurst, salami to jamon — as processed and containing potential carcinogens. Over time, with trickery and marketing, we have forgotten which foods are made artificially for us. A study recently found that about 60 per cent of dietary calories of US adults came from ultra-processed food and a further 10 per cent moderately processed.

Our love of bacon comes at a cost. Most bacon you buy has nasty added chemicals like nitrites and phosphates that are used to bind the meat scraps and retain water. This is the milky liquid that oozes out when you first put them in the pan. When bacon is heated the mix of the natural and artificial chemicals produces a whole range of other chemicals, many of which the WHO label as carcinogenic. It appears that the more added chemicals and extractions used in the process, the greater the risk of producing carcinogens.

It is possible to find cured bacon using simple methods that are hundreds of years old. There are villages in Italy that produce their own salami without having to add the usual myriad colourants, enzymes, extractors, acids, emulsifiers, binders, bulkers and preservatives to convert industrial meat into something edible. What should make us all nervous is that the label is misleading and doesn’t allow the consumer to tell the difference between a fake and an artisan salami.

A general rule of processing food means that the cheapest ingredients are combined from around the world using bland frozen products that lost their nutritional value and flavour long ago. To make them look appetising and taste of something resembling food they add as many chemicals as they can get away with.

This was easy — there are thousands of approved additives to choose from — until E numbers hit the headlines and the public started equating these with ill-health. As Joanna Blythman shows in her excellent behind-the-scenes book Swallow This, the industry has got round this by using names and varieties that sound less deadly. These include replacing colourants with vegetable extracts and using the word malted rather than modified starch (E1422). They also still have large amounts of salt, sugar and fat added in the right proportion to achieve the magical bliss point that make customers return.

Although many of the chemicals and additives approved in processed foods are theoretically harmful there is surprisingly little research performed on humans and no high-quality trials. The closest data we have comes from very large observational studies of the habits of hundreds of thousands of people. They found that regularly eating processed meats carried an increased risk of heart disease, obesity and an increased risk of colon cancer. These risks are considerably higher than just eating red meat.

Is there a unifying factor that explains how processed food is bad? The old scare story of high fat content had some truth in it when we had many foods with artificial trans fats in them — but these are nearly absent in most processed foods in sensible countries. We now know, after being told the opposite for years, that natural saturated fat as part of a balanced diet (as in the Mediterranean diet) is not harmful in moderation for most people. So what is the common factor that is upsetting our bodies?

Many substances used in the processing of food don’t actually appear in the final product or on the label. All substances that get added to manufactured foods need to be approved as safe for consumption in humans. These tests usually involve giving enormous amounts to poor lab rodents and seeing how their livers and organs react.

But we have probably been testing these chemicals in the wrong animals. In the last year several labs have started to test them unofficially in tiny animals — that you need a microscope to see — called microbes. One hundred trillion or so (ten times more than human cells) live happily in our guts feeding off our food and producing vitamins and chemicals that keep our immune systems healthy. When our microbes are disrupted, it makes us sick. It turns out that our microbes dislike these ‘harmless’ substances like emulsifiers, preservatives and artificial sweeteners, making them produce unusual obesity- and diabetes-promoting chemicals and killing off many friendly species. Microbes in our mouth can also convert nitrites to nitrosamines — a classic carcinogen.

Back in human guts, losing your diversity of microbial species (there are usually thousands) is associated with an increased risk of many diseases as well as obesity. Our gut microbes are pretty sensitive. I fed my (initially willing) student son Tom a McDonald’s burger and nuggets diet for 10 days and he lost 40 per cent of his species diversity. (This could have been due to the surge of chemical additives as well as the effects of nutritional and fibre deprivation.) Two weeks later Tom’s poor microbes hadn’t recovered to pre-Big Mac levels.

So should you be worried about all the chemicals in processed food? The answer is yes. We should be very concerned about what food manufacturers are getting away with. When there are often ingredients that don’t have to appear on the label it’s almost impossible to know what we are eating and how it affects us. All of these chemicals could be upsetting our gut communities. Until the regulators and governments start prioritising the health of humans and their gut microbes above cheap food prices it will continue to be virtually impossible to avoid processed foods. I suggest we be wary of food in slick packaging and long shelf lives and stick as much as possible to this maxim: if your great-grandmother wouldn’t recognise it as food, avoid it.

Tim Spector is professor of genetic epidemiology at King’s College London and author of The Diet Myth: The Real Science Behind What We Eat


  • vlc

    Great article. Accurate and straight to the point. Thank you. I shall be reading your book and as much of your other articles as I can find.

    • Alan Marson

      Oh – I get it now its about promoting a book ! a fiction novel of course – or am i missing something

      • vlc

        Yep, you’re missing what’s in the book 😉

  • Thomas Baird

    Spot on. Saturated fat doesn’t cause heart disease; carbohydrates and sugar do.

    Since 1983 when the U.K. dietary advice advocating a low fat, high carbohydrate diet was produced, both diabetes and obesity have soared four-fold.

  • countrylad

    There is a lot of evidence that bacon and other processed meat is carcinogenic. This is the first article I have seen that actually suggests that might be due to the nitrates and other additives. ‘Proper’ bacon is made of simply pork and salt (plus natural aromatics possibly) so should be no more carcinogenic than fresh pork. The fact that it is points to the additives being the problem.

    • vlc

      Not so much the nitrates as the nitroamines generated after cooking the nitrated meat at high temperatures. e.g. Might be wise to add pepperami only after the pizza is cooked.

  • Wolfgang Haak

    Great article – do you have sources available? Like what’s (not) on labels like the Greek-Style Yogurt? Or the microbial research? And what books would you recommend to read to find out about hidden ingredients and what to look out for?
    Thanks!

  • Speakerofthe House

    What a bunch of unscientific Male Bovine Excrement, filled with buzzwords such as “industrial meat”. Gag, puke.

  • David Frew

    if you really think you are on to something with this conspiracy theory bullshit, do a proper fucking experiment before you start shaming every single manufactured food and spreading fear that we are poisoning ourselves every time we eat a bag of salad. If you think that a particular preservative has a damaging effect on the gut microbiome, do some fucking science and produce some real fucking evidence. Don’t feed your son a Big Mac and take up valuable testing resources in your laboratory to create a meaningless anecdote in order to fill a thousand words in the Spectator and shift a few fucking books. Demonising processed food is not something to be done lightly, it has real consequences and can cause real harm. Do not make people think that perfectly safe and frequently eaten foods are dirty, dangerous, damaging or unclean. Have some fucking responsibility.

    • lolexplosm

      At least quote your source. 😉

  • lolexplosm

    So many [citations needed].

    Is this actually written by the same respected professor?! Oh an anecdote with speculatative conclusions, a fantastic piece of strong evidence. No mention of any specific chemicals causing specific effects? Big food conspiracy theories? This article reads like a blog entry from a wellness guru advertising their latest products. Sure the gut microbiome is an interesting field and deserves to be highlighted and researched but we need more studies rather than potentially prematurely label it as a panacea. As an academic, he should know better but I guess it’s fine if you have a book to sell.

    A good rant on this post was done by the Angry Chef. http://angry-chef.com/blog/a-convenience-truth-part-3

  • Alan Marson

    Silly – Silly me ! Just realised – I was taking what was written in this blog as being serious !
    Now i see it is just a poor piece of use of a social media plot to sell a book
    – will look out for it soon in the fiction section of my local charity shop

  • Jeff

    Gated Communities

    Gated communities are taking on an important role in modern politics. Donald Trump grew up in a gated community, and made his fortune building gated communities that illegally exclude African-Americans. Trump’s approach is not based on ideology, but on consumer demand, and in particular, the demand of the working class to live in a place where there are no minority groups, criminals, wierdos or politically correct (Catholic educated) people.

    A gated community has a number of characteristics. There is ideally a six metre high concrete wall to keep out intruders. When the wall surrounds a very large number of houses, the average cost of the wall becomes insignificant. Getting past the security guards is like going through customs. Hence there is no crime in a gated community, and children can roam unsupervised in complete safety. Parents can be sure their daughters will not encounter males that would be unsuitable sons-in-law.

    Allotments are typically quarter-acre or five acres (one-tenth or two hectares). Houses are fireproof and of a similar appearance. Services are provided by underground ducts, including pneumatic mail delivery. Television and internet are unobtrusively censored.

    There is a shopping centre with a supermarket and other key shops. Prices are controlled to prevent gouging. There is a club for men and older boys from which women are excluded. On the top of the shopping centre is a hospital and old people’s home overlooking a race track and playing fields.

    There is a non-denomination church, which has leather sofas instead of pews, and wallpaper with pictures of saints like in an eastern orthodox church. The priest is a family man employed by the management committee. There is a co-educational school, so that if children conceive a passionate desire for a classmate, it will be someone of the opposite gender. The school has international baccalaureate and no homework.

    Once people move into a gated community, it occurs to them that, instead of their having to move into a gated community, it would be better if the “undesirables” were forced to live in ghettos, or were kicked out of the country altogether. No doubt this is what Donald Trump has in mind. The Conservative Party should take on board this trend in modern living and become the party for people who live or would like to live in gated communities. eo