5 things you probably didn't know about processed food

When I began to research the many ways in which we manipulate food for a book on food fraud back in 2014, I unearthed horrendous stories of deceit – from rotting meat dipped in bleach and sold back into the human food chain to fake milk made from urea, shampoo and milk powder. Horsemeat seemed tame by comparison.

Equally concerning, however, was what I learned about the perfectly legal ways in which we process food that most of us know little about – enzymes that mature cheese in a fraction of the time and patented chemical dips that keep cut fruit fresh looking for a month, to name a few.

These would be the stories for my next book. And yet, as I delved further into the topic, understanding both the science and the contexts in which these foods evolved, I grew more comfortable with the world of processing. Or at least more capable of discerning which processed foods aligned with my values and which did not. Instead of an exposé of the food industry, the book became an opportunity to start a rational discussion about processed food.

It was the first hominins in our ancestry to pick up a stone tool and pound a tuber to make it edible, or slice a piece of flesh from an animal carcass, who set us on this course of processing food.

Around 2 million years ago (though this is still debated) our ancestors learned to control fire and began to thermally process (cook) their food. The first evidence of grinding grains to make flour is from an archaeological site in Israel’s Rift Valley that’s estimated to be 23,000 years old – before the dawn of agriculture.

Read more about the history of food:

• Ancient humans stored bone marrow in earliest example of preserved food
• Unbeerlievable! Ancient Egyptian ale recreated from 5,000-year-old yeast
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Around 9,000 years ago, humans began to milk their domesticated animals, as evidenced by milk fat residues found on excavated pottery shards – hints, perhaps, of early cheesemaking. Ancient Egyptian hieroglyphs and artist depictions from 3,500 years ago are the first evidence of breadmaking.

We have tinkered with these ancient processing methods – arguably for better and for worse – to meet the changing demands of evolving cultures. In the last century our tools for tweaking these methods have become so sophisticated, however, that it has caused us to question whether we have gone too far. But perhaps our early ancestors posed these same questions as they watched meat brown (the Maillard reaction) over an open fire for the first time.

Our long association with food processing has shaped us as a species. When our early ancestors started to make food easier to eat and digest through processing, it meant individuals with marginally less powerful jaws and smaller teeth were able to extract just as many nutrients from their food as their peers with more powerful chops.

And so began a trend toward increasingly smaller teeth and jaws – human faces began to shrink. The resources used for mastication could be diverted to other things, such as bigger brains.

Processing food also meant that less time was needed for chewing and digesting food, and while some of this gained time was inevitably used to process food externally, it also meant more time for collecting resources and socialising. Not to mention, grinding food with stones rather than one’s teeth, would have freed up mouths for developing complex languages.

After a couple of million years of evolving with processed foods, our bites have become less important. In fact, the third molars (wisdom teeth) of modern humans often don’t even form, or at best make a painful attempt to break through the gums. This long dependence on softer, processed food has often been blamed for the prevalence of misalignments, overbites and overcrowded teeth among modern humans. One might say that we have become such bad chewers, we are now dependent on processed food.

Processing milk into cheese arguably led to the evolution of lactase persistence – the ability to digest milk into adulthood. This genetic mutation for milk tolerance has become well established in some populations – 96 per cent among British people – in a mere 10,000 years of dairying, which is lightning fast in evolutionary terms. It might not be a mutation worthy of the X-men, but it is nonetheless an important part of our evolutionary history.

Processed food has changed our DNA and it has shaped the way we look. The concern, of course, is that the ultra-processed foods of today are continuing to shape us, potentially into insulin resistant, obese, hyperactive individuals with increasingly bad teeth. Not exactly a great step forward in human evolution.

While it is easy to point fingers at profit-hungry food manufacturers as driving the trend toward more highly-processed food, there are a multitude of factors that have determined the path of processed food (though it must be said that some finger pointing at industry is still needed).

Wars have, on many occasions, propelled innovation in food processing. The loss of British and French seamen during the Napoleonic Wars, required new thinking around food preservation, leading to tinned food. War has created shortages that lead to innovation. Margarine was developed as a result of shortages in edible animal fat in the 1860s and Nutella was the product of cocoa shortages during the Second World War.

In the early 20th Century, legislation was introduced in the UK that required everyone, including household servants, to have half a day off each week, and young women who normally would have gone into domestic service were lured to better-paid factory jobs. The middle-class woman of the house was now responsible for more cooking, generating a niche for convenience food. Pre-made sauces, biscuits, tinned soups, powdered custard and cereals adorned the pantries of those who could afford them.

In the 1950s, the first ready-made meal was put out into the market in the US. It was Swanson’s frozen turkey dinner and it came about because C.A. Swanson & Sons had overestimated how many turkeys Americans were going to eat for Thanksgiving in 1953.

It was an innovation spawned out of surplus rather than shortages. Yet it also provided a new option for 1950s housewives, many of whom were torn between expectations of domestic duty and work outside the home. Hunger, poverty, war, legislation, changes in domestic situation, shortages, surpluses, the environment and human health: all of these have, and will continue to be, drivers of food innovation.

One of the many concerns about processed foods is the long list of complicated ingredients that require a degree in chemistry to decipher. Many of these substances are added to enhance flavour, preserve colour, improve consistency, keep ingredients mixed and extend shelf life, but do we need all these ‘extras’?

Yes, sometimes we do. And as evidence, let me tell you a story about a tortilla wrap. One morning, faced with an absence of wraps in my fridge and an empty lunch box for my son, I swiftly mixed together the ingredients for a flour tortilla. I glowed with pride as I skilfully enveloped cheese and salad in the homemade, hot-off-the-grill wrap. I was, in that moment, Super Mum. Five hours later, as I bit into my own wrap, leftover from the morning, I nearly chipped a tooth. It was a rock.

Factory tortilla wraps contain an additive known as a humectant, which keeps them soft and pliable for longer. This ingredient, like so many others, has 2 stories. Story 1: it is a substance – listed on food labels as E422 – that was once used in anti-freeze and is also used in the production of nitroglycerin, the active ingredient in explosives. Story 2: it is glycerol, a simple molecule that forms the backbone of all fats found in plants and animals, and it is added to commercial tortilla dough because it forms strong bonds with water.

Read more food Q&As:

• Whatever happened to irradiated food?
• I’m in my 30s and I never follow the nutrition labels on food. Am I about to die?
• Do I really need to leave my food to stand after it comes out of the microwave?
• Are there any animals that prepare or cook their food?

Both stories are true, and yet each evokes a very different response when we think about this ingredient in our food. The point being, that processed food often does have far more ingredients than the equivalent home-made version would, but we need not fear all of these ingredients (though some are certainly worthy of concern).

The industry and labelling laws need to support consumers in being able to navigate these complicated labels so that we can decide for ourselves which are, or are not, acceptable to us.

We have been captivated by the convenience of the ready meal. It’s rise in popularity has been attributed to many things: women working outside the home, more single-person households and single parents, people living longer and more independently, an addiction to social media and television, laziness and lack of culinary skill.

And despite the popularity of ready meals, they have earned a reputation for being high in saturated fat, sugar and salt; low in nutrients; over-packaged and of questionable authenticity.

However, like all food, not all ready meals are equal. Some fall within the recommended caloric intake for a single meal, while others do not. But then again, a recipe book contains energy-dense ‘comfort food’ recipes as well as healthier recipes.

In fact, when the nutrition labels of ready meals have been compared with popular recipes for the equivalent meal, the ready meals have often come out ahead in terms of meeting the recommended ratio of calories from carbohydrates, fibre content and saturated fats. Ready meals, consistently lose out to recipes for salt content, however.

When comparing the environmental impact of a ready meal to a home-cooked meal, there are also some surprising outcomes. If all the ingredients for the home-cooked meal are purchased from butchers and greengrocers with minimal packaging, it might nudge out the ready meal in environmental scoring.

However, if the ingredients are bought at a supermarket where they are likely to be more packaged, then the ready meal might take the win. It depends on where the ingredients are sourced from and whether gas or electrical appliances are used in cooking. The point being, it is not as straightforward as one might initially think.

Discover more about the future of food:

• The future of food: what we’ll eat in2028
• The Big Mac and the bee
• The artificial meat factory – the science of your synthetic supper
• Ultra-processed food and the risk of death: will fish fingers and fizzy drinks kill you?

Processed food is an integral part of our diet and processing methods may help us to overcome food insecurity – one of the greatest challenges we face as a society. To paint all processed food with the same brush of disdain is irrational and unfair. It has shaped who we are and we, in turn, must shape its evolution, directing it toward innovations that bring about the equitable distribution of safe, nutritious food, rather than driving profits of large corporations.

• This article was first published in March 2018