Whenever Dr Yasmin Razak sees a healthy patient in their 90s at her London GP surgery, she asks them what they do to look after themselves. "They say every time: 'I make my own food and I don't eat out'. They either have an allotment or grow food in their garden."
The secret to long life looks straightforward, then. Dr Razak's nonagenarians, who also cite regular walks, do not rely on the convenience foods, takeaways and ready meals that so many of us consume today. "It goes back to simple, basic things," agrees Dr Razak, a diabetes expert and adviser to myGP, the NHS-accredited health management app.
A growing body of research into the effects of ultra-processed food on our health would appear to support the idea that cooking our own food matters. According to a study of 900 elderly Spanish men and women carried out by the University of Navarra, as consumption of ultra-processed foods – such as frozen pizzas, hot dogs, chicken nuggets and instant noodles, chocolate bars, fizzy drinks, sweetened breakfast cereals and flavoured yoghurts – increased and consumption of fresh food decreased, the likelihood of having shortened telomeres rose dramatically. Short telomeres indicate biological changes at a cellular level and are linked to ageing.
In short, the findings suggested the modern diet was likely to be causing the cells to age faster.
Those eating the most ultra-processed foods were also found to be more likely to have a family history of heart disease and diabetes. Depression, high blood pressure and mortality were linked with high consumption of them, too. Separate research in 2018 suggested UK families bought more ultra-processed food than those in any other European country. This study, led by Professor Carlos Monteiro, from the University of Sao Paulo, found 50.7 per cent of the British diet was ultra-processed. This, despite our notion that we've become a proud nation of foodies.
So how did we get here? And how worried should we be?
Modern processed food has a long history. From preserving it in cans (a technique invented almost 200 years ago) to pasteurising it (a process discovered in 1864), we have continually sought ways to keep comestibles fresh, attractive, safe and tasty. But during the second half of the 20th century, a new type of food crept into Western diets: that was made mostly or wholly from substances "extracted from foods or derived from food constituents": things like sweeteners, preservatives and colourings. It typically goes through multiple processes in the factory.
It's quick, it's moreish – and it's everywhere. It's hard to avoid and, eaten in large quantities, it's apparently doing us untold damage.
The problem is it makes our lives easier. "Cooking from scratch is more labour-intensive," says Sam Bilton, a food historian. "So with women going into the workplace, it's not surprising it took hold as it did."
Other societal advances came into play, too. In 1970, only 3 per cent of Britons owned a freezer. By 1995, more than 96 per cent of households had one. The first domestic microwave oven was sold in the UK in 1974. Today, they are ubiquitous.
These technologies allowed for the storage and quick reheating of mass-produced, highly processed food, now credited with liberating women from the kitchen. But at what health cost? Last year, a study of 45,000 middle-aged people led by Paris-Sorbonne University found that every 10 per cent increase in intake of ultra-processed food was linked to a 14 per cent increased risk of death within the next eight years.
The findings were attributed to the fact they tend to be energy-dense, rich in refined carbohydrates, saturated fats and salt, and contain low dietary fibre – features associated with various life-threatening diseases.
Dr Razak says: "People don't tend to eat them in moderation because they are often high in carbohydrate and so don't fill you up, The body craves more, so it becomes a vicious cycle.
"The answer is obvious: eat more fresh food. But why is it people aren't able to do that? That's the discussion we need to have. It may not be affordable or accessible, and it's not as easy for people who haven't cooked before to know how to cook. People have very busy lives."
But for Anthony Warner, the self-styled Angry Chef and food writer, the case against ultra-processed food is less clear-cut. Just because those who eat more of them have worse health outcomes isn't proof the food itself is to blame, he says. Correlation, in other words, is not causation.
"I can think of all sorts of factors that would influence it, including socioeconomic [ones]," he says. "It's not to say there's not a problem with certain types of processed foods, but to lump them all together I think is ridiculous and unscientific."
Instead of demonising food people turn to often because they're busy or poor, or perhaps less able to cook for themselves due to old age or disability, we'd be better off trying to understand their reasons for doing so, he suggests. "We look at the lifestyle of people who are healthier and assume that if we translate that on to people who are less healthy then they'll magically become healthier. That ignores things like public health inequalities."
It's perhaps too soon to say if the tide has started to turn. Many of those who, pre-pandemic, lost several hours of their week to commuting say working from home has given them more time to cook healthy meals from scratch. The UK government is, meanwhile, trumpeting its plans to reduce obesity and type 2 diabetes (conditions associated with worse coronavirus outcomes). On the other hand, in-home consumption of crisps, chocolate and biscuits also increased during lockdown.
There is no consensus regarding the responsibility of the individual, as opposed to the role of government in changing behaviour by nudging, legislating and taxing, or how much we should blame the food industry. Last week, however, action to tackle obesity was stepped up when cafes, restaurants and takeaways were handed new Public Health England guidelines asking them to reduce the calorific content of their wares by 20 per cent by 2024.
Dr Razak believes the role of the health service, meanwhile, needs to change from just treating illness when it happens to focusing more on preventing it.
So doctors need to promote healthier lifestyles, including cooking our own meals from scratch?
"Yes, that is 100 per cent our role," she says.
"There are cheap options for quick, nutritious, healthy foods. A stir-fry takes 10 minutes. We say it's hard but maybe we make it hard. We say people are too busy, but we're rushing now only to die younger.
"I think what people don't realise is eating more healthily gives them their time back later, in the form of a longer life."
Packaged supermarket sliced bread
If it contains emulsifiers or colourings, this bread counts as ultra-processed. Mass produced bread can contain up to 26 ingredients and additives and white bread can contain highly processed white flours with a higher glycaemic index (GI), meaning they are digested quicker, giving you a raised blood glucose level and spiking your insulin levels.
Pre-packaged ready meals
These commonly contain high levels of salt, sugar and fat and low levels of other nutrients your body needs.
These often make health claims such as being high in fibre. The unhealthier ones are also high in additives and sugar.
Sausages and bacon
Processed meat has been classified by the WHO as a group 1 carcinogen as evidence has linked them to stomach and bowel cancer.
If it contains preservatives, sweeteners, stabilisers or colourings, it is ultra-processed.
The Daily Telegraph UK