Читать книгу Extra Time: 10 Lessons for an Ageing Society - How to Live Longer and Live Better - Camilla Cavendish - Страница 9

WHAT IF THE KIND of ageing we dread is not, in fact, normal? What if our modern accumulation of chronic diseases, followed by a prolonged twilight zone, are largely a consequence of Western habits, which have distorted the true path of biological ageing?

It’s generally assumed that how we age is down to luck and genetic inheritance. But for most of us, genes write only 20 per cent of our fate. The other 80 per cent is down to environmental factors: what we eat and drink, how stressful our lives are, whether we live amid pollution, whether we exercise (and how often).

This means that we already hold many of the keys to Extra Time in our own hands. Decades of research show that we don’t have to succumb to deterioration from the age of 50, our arteries and joints gradually stiffening, and puffing our way into chronic disease. We can fight to stay relatively youthful right up until 90, and even reduce our risk of dementia, by eating better and becoming far, far more active. A raft of studies around the world have, in fact, identified exercise as the single most powerful predictor of whether we will age well.¹

‘Miracle Cure’, a report from the Academy of Medical Royal Colleges, finds that the big four ‘proximate’ causes of preventable ill health are smoking, poor nutrition, lack of physical activity and alcohol excess. ‘Of these,’ the report says, ‘the importance of regular exercise is the least well-known. But relatively low levels of increased activity can make a huge difference’. The report concluded that 30 minutes of moderately intense exercise, five times a week, can reduce the risk of developing heart disease, stroke, type 2 diabetes, some cancers and even dementia.²

This needs to be much, much better-known.

If Life Is a Marathon, We Need to Sprint

‘If exercise was a pill, everyone would be taking it,’ says Norman Lazarus, 82, as we walk through a violent downpour outside his office at London Bridge. My feet are drenched even under my umbrella; he only has a jaunty red cap on his head, but he shrugs off the rain. A short, wiry man with a stubby white moustache, Lazarus is a long-distance cyclist who regularly covers distances of 60 miles. He has just come back from cycling 180 miles in Oxfordshire with his daughter at the weekend. ‘Exercise is great,’ he says, in his strong South African accent. ‘For the body, the mind, for muscles – you name it.’

Lazarus is not just a biking fanatic, he is also emeritus professor at King’s College London, where he has co-authored a study into amateur endurance cyclists like himself. The older cyclists in the study – aged between 55 and 79 – were found to have similar immune systems, strength, muscle mass and cholesterol levels as those who were only in their twenties.³ On those criteria, the older cyclists had barely aged at all. The researchers could not tell how old they were by looking at their physiology on paper, only by meeting them and seeing their wrinkles.

The King’s researchers believe that endurance sports, including cycling, swimming and running, may protect the immune system by boosting the number of T-cells in our blood. These protective white blood cells are thought to decline by about 2 per cent a year from our twenties onwards, making us gradually more susceptible to infections and conditions like rheumatoid arthritis. But the older endurance cyclists had almost as many T-cells as 20-year-olds – a protective effect that no medicine yet invented can provide.

To qualify for the study, men had to be able to cycle 62 miles in under 6.5 hours and women had to be able to cycle 37 miles in 5.5 hours. That’s impressive. But all were amateurs, not professionals. Some, like Norman Lazarus, had only taken up cycling in their fifties. And they loved it. When interviewed, they reported not only managing the distances fine, but feeling fabulous as a result and wanting to do more.

Lazarus cycles with an amateur group. He also goes to the gym three times a week and does what he calls ‘anti-gravity exercises’ – lifting weights. Many of his friends cycle, as does his wife, who is 85. ‘We’re all going to die, yes,’ he announces breezily, ‘but none of us are ill at the moment. One day we’ll get to the point where we can no longer fight infection. But then hopefully, it will be quick’ – he pulls his hands towards each other to demonstrate the narrowing period of illness, the mercifully brief end he anticipates when he and his friends eventually move from ‘Young-Old’ to ‘Old-Old’.

Do the cyclists keep going because they are unusually healthy, or are they healthy because they cycle? Lazarus believes it’s the latter. What we see in the cyclists, he insists, ‘is true biological ageing, free from the problems caused by inactivity’.

If you wanted to see what true biological ageing might look like, you could charter a boat. In Ikaria, a beautiful Greek island off the west coast of Turkey, one in three inhabitants live into their nineties and dementia is rare. Ikarian men don’t get cancer or heart disease very often, and when they do, it develops eight to ten years later than in Americans. Ikarians also report considerably less depression.⁴ Their life is very much an outdoor one – it’s said to be hard to get through a day in Ikaria without walking up 20 hills – and that might just have something to do with it.

Ikaria is one of the Blue Zones (see here), where people live exceptionally long lives in good health. There doesn’t seem to be any genetic singularity; the secret is lifestyle. There has been much talk about the plant-based diets eaten in Blue Zones and far less focus on exercise. But whether in Sardinia, Okinawa or the other Blue Zones, it’s clear that these hearty, long-lived people lead very active outdoor lives.

This is not ‘exercise’ in a gym, pumping iron to music videos. It’s movement built into daily life, to do tasks that the rest of us have replaced with cars, robot-vacuum cleaners and other devices. We have saved ourselves hours by not fetching water, chopping wood or tending our vegetables. But has it lost us our agility? Activity maintains muscle mass, reduces stress by connecting our primitive brain to its old hunter-gathering functions and improves immunity by triggering a cascade of chemical signals in the body. Whenever we take the lift rather than the stairs, or drive rather than walk, we may be losing more than we realise.

Until now I’ve thought of endurance athletes as freakish, as having either a genetic predisposition or a crazy obsession to compete. But now I wonder. Stunning results have been seen in an otherwise normal group of American septuagenarians who started running when it became fashionable during the 1970s, and stayed hooked. Over the next 50 years some went on jogging, others took up cycling or swimming or working out, but they did it regularly – and as a hobby, not to compete.

To the amazement of the researchers, the muscle strength of these seventy-somethings was almost indistinguishable from 25-year-olds, with as many capillaries and enzymes. Their aerobic capacity was 40 per cent higher than people of their age who were not regular exercisers. The researchers at Ball State University, Indiana, concluded this made both the men and the women biologically 30 years younger than their chronological age.⁵

It’s impossible to overstate the importance of this finding: it suggests there is hope for us all.

Younger Next Year?

In terms of fitness, human beings keep pushing the boundaries of what is thought possible. The ‘Masters’ sporting events are a kind of amateur Olympics for those aged between 35 and 100. These regularly generate headlines about extraordinary feats – like in 2016, when Japanese athlete Hiroo Tanaka ran the 100 metres in 15.19 seconds. Tanaka’s time was nowhere near the Jamaican Usain Bolt’s world record-setting run of 9.58 seconds in the final of the 2009 World Athletics Championships in Berlin. But Bolt was 23, Tanaka was 85.

Masters athletes don’t just sustain performance to advanced ages, they have also been improving constantly over time. Their athletic performance has improved ‘significantly and progressively’ in the past 40 years. And the greatest magnitude of improvements has been made by the oldest swimmers and runners, who are over 75.⁶ This suggests that we may be only in the foothills of understanding the ‘Young-Old’. One of the Holy Grails for serious sportspeople – the maximal rate of oxygen consumption or VO2 max – declines at half the rate in Masters athletes as it does in their sedentary peers.⁷ One explanation is that regular aerobic exercise brings more oxygen to the muscles. The more we do, the more our heart and circulation respond, to get oxygen round the body.

Intensive working out doesn’t massively extend life. Olympians gain only 3 extra years over normal folk on average, according to a century of Games records.⁸ But they do gain a significant health advantage. This is greatest for cyclists and rowers, apparently; but even playing lower-intensity sports like golf can be positive. Commenting on the research, Professors Adrian Bauman of Sydney University and Steven Blair of South Carolina University stressed we don’t all have to be Olympic athletes to reap the benefits of exercise and win a ‘personal gold medal’. They urged governments to do far more to improve physical activity.

We don’t all have to run marathons. Above a certain level of athleticism, you can’t advance your health, only your performance. ‘Think back over 40,000 years of evolution,’ says Norman Lazarus. ‘We had to be fit to hunt. But you wouldn’t chase an animal for 15 miles – that wouldn’t be worth it, just to get, say, a pound of steak. You’d stop after a mile and keep tracking.’

That’s a relief. I don’t enjoy running – I can only sustain it with friends, shuffling through corny hits on my headphones. But Lazarus does make me wonder how many of us modern office workers would have the stamina to track our prey for miles, if we were suddenly transported to a desert plain. Nervously, I ask whether he thinks I am doing enough. I do British Military Fitness twice a week in my local park, cycle to meetings if I can and play a slow game of tennis once a week. I don’t mention that I achieve this only on good weeks. ‘Perfect,’ he beams, as if I have made it into a club. ‘Do what you enjoy.’ He pauses. ‘But’ – he fixes me with a glare – ‘your goals do need to be sufficiently ambitious.’

Ambition is frankly what most of us lack. When I started researching this book, I thought I was pretty fit. Now, I realise with horror that I’ve slumped into a rather comfy regime. My tennis game is doubles, not singles, and includes gossip and cappuccino. I’ve dropped into the slow group at Military Fitness. I don’t work up a sweat as often as I used to. And what many experts seem to believe, though few dare to put it so crudely, is that sweat is the measure which really matters.

Ambitious is also what our health systems are not. Older people are so often told: ‘don’t overdo it’. Yet from the age of 50, muscle and bone mass start to decline by around 2 per cent a year.⁹ We should be doubling down on strength training and aerobic fitness from that age. Instead, we spend an awful lot of time sitting down: something we are now told is as dangerous as smoking.

Don’t Just Sit There – Do Something

The idea that sitting is as dangerous as smoking sounds absurd, but evidence from all over the world, from Norway to Canada, suggests a lack of low-level physical activity is cumulatively crippling. It puts us at much greater risk of getting the same nasty diseases which exercise can help to prevent.¹⁰ That doesn’t mean it’s your fault if you get cancer: I abhor the invidious trend which implies that people who fall sick didn’t do enough sit-ups or eat enough broccoli. But so compelling is the evidence, I predict that in 20 years’ time it will seem as foolish not to exercise every day as it does now to keep smoking.

We’ve known that sedentary occupations were dangerous since 1953, when J. N. Norris and colleagues reported in The Lancet that London bus drivers were more likely to suffer heart disease than London bus conductors.¹¹ This was a brilliantly elegant piece of research. The two groups of staff worked the same hours, breathed the same air and hailed from similar backgrounds. The main difference was that the drivers were sitting down all day, the conductors were moving around taking tickets and chatting to people. Without knowing it, the conductors had chosen a far healthier job.

Sitting down for more than an hour at a time sharply decreases the enzyme LPL, which burns body fat and produces good cholesterol.¹² It can also weaken leg and hip muscles, which makes older people more likely to fall. A weekend workout will not erase the effect of prolonged hours sitting in our cars, at our desks or at a screen. In the US and UK, only a quarter of us are apparently moving around enough during the working day, and in Australia, only a third. Older adults have the lowest levels of physical activity, with only 7 per cent of Brits achieving the recommended minimum of five times a week.¹³

It’s not easy to improve, especially if you earn your living driving a truck or typing. Fitbits may help: people who take 10,000 steps a day apparently have lower blood pressure, more stable glucose levels and better moods than those who don’t.¹⁴ There’s no special magic to the 10,000 target – it apparently derives from the first pedometers sold by a Japanese company in the 1960s, which were called manpo-kei, or ‘10,000-step meter’. Some people think 15,000 steps better resemble the daily distances covered by the average Ikarian or Okinawan, but the point is to keep trying, every day.

Could What We Think of as ‘Ageing’ Actually Be Lack of Fitness?

‘We have a muddled concept of ageing,’ says Sir Muir Gray, Clinical Advisor to Public Health England, former Chief of Knowledge for the NHS, and author of the wonderfully named book Sod 70! ‘Society perceives disease, loss of fitness, dependency, dementia and frailty as inevitable,’ he says. ‘But they are not.’

With a shock of white hair at 73, and a wiry energy, Gray clearly has no intention of slowing down. He arrives sporting a pair of black Nike trainers and announces in his rasping Scottish brogue that he has walked to our meeting – I dare not ask how far since it may put me to shame. Gray is passionately convinced that we confuse the effects of true ageing with what is mainly a loss of fitness, caused by far too little activity. ‘People with long-term conditions and those who experience pain,’ he says, ‘often mistakenly believe that exercise will make things worse, rather than understanding that the more conditions you have, the more you need to improve the four aspects of fitness: strength, stamina, suppleness and skill.’ Some doctors prescribe exercise – for osteoarthritis, for example – but not for many other conditions.

Gray believes we could save billions if we made it normal to expect people of all ages to be active. ‘Almost every week, there are headlines about the rising cost of health and social care,’ he explains. ‘The blame is usually placed on the rising numbers of older people, as if the requirement for social care was an unavoidable consequence of ageing. But exercise can reduce the need for social care.’ In 2017, he and colleagues calculated that the UK could save several billions a year from ‘even modest improvements in fitness’ to stop older people crossing the line from independence to dependence: needing carers or going into a home.¹⁵

Unless we are rigorous about keeping active, natural decline will be accelerated by unnatural stiffness, extra loss of muscle tone and immunity, and hardening of the arteries. Gray calls this the ‘fitness gap’, which opens up between how able we are and how able we could be. This starts, imperceptibly, in our thirties. By our sixties, we may find we cannot do the basic things we want to do: run for a bus or climb the stairs, for example. If we don’t heed the warnings, we may end up crossing the line into dependency.

The fitness gap can be narrowed, Gray argues, from any age. Even 90-year-olds can improve their strength with relatively small amounts of exercise.¹⁶ Three months of balance and gait training, and mild weight-bearing exercises, can reduce falls – which are responsible for five times as many hospitalisations among the over-65s as any other injury. They can make the difference between whether someone remains independent, or crosses the line into dependency on others.

In the UK, 10 per cent of ambulances are called out for older people who have fallen over.¹⁷ Half of those who fracture a hip subsequently become reliant on others. Yet physical activity can halve the risk of falls.¹⁸ It also strengthens muscle and bone density, making fractures less likely.¹⁹ From a cost–benefit point of view, let alone a humanitarian standpoint, we should be investing in such programmes in every community.

A little bit of imagination would go a long way here. One company, MIRA Rehab, is using gaming software to improve balance in people aged 3 to 102. In one game, you play a piano by sitting down or standing up: each movement sounds a different key. One stroke victim was so keen to play the whole tune, says MIRA’s founder Cosmin Mihaiu, that he managed to sit down and stand up more times than his therapist had imagined possible. A trial has found statistically significant improvements in balance and pain among people who played the games 3 times a week for 12 weeks.²⁰

Yet many 90-year-olds who want to exercise come up against the prevailing attitude that exercise is for young people and that older people should relax. We give people pills to stave off pain rather than prescribe exercise which might resolve it. In England, everyone over 60 gets prescription medicines for free. Ontario, Canada, has just followed suit by eliminating the cost of prescription drugs for many senior citizens.²¹ But gym memberships aren’t free, nor is physiotherapy. Instead of encouraging people to take responsibility for their own health, helping them to understand their bodies and strengthen their muscles, we are making it easiest to pop a pill. That sends the wrong message.

If we were serious about keeping people from crossing the line to dependency, we would put huge effort not only into preventing falls, but also delaying the onset of dementia. Much of the focus has been on finding a cure, which as yet shows no signs of success. But if we could delay onset in individuals by only five years, we would reduce the number of cases by a third. That’s because dementia is a disease which usually hits late in life.²²

The 2,500 Welshmen Who Showed How to Stave Off Dementia

In 1979, an eager young scientist called Peter Elwood trudged up and down the streets of Caerphilly, a valley town in South Wales, knocking on doors. He and his team asked every man between the ages of 45 and 59 if they would let themselves be poked, prodded and interviewed by medics every five years to track their health.

They must have been very persuasive because they got 90 per cent of the candidates – 2,500 Welshmen – to agree.

Caerphilly is set in stunning countryside and is home to one of the greatest medieval castles in Europe, but it’s not a rich area. Elwood picked it, unromantically, because there was a high incidence of heart disease.²³ Elwood had been a part of the team which proved that aspirin could protect against heart disease and he was hoping to find a test which would show who would benefit from aspirin most. He failed to do that, but over the next 35 years of the study he discovered something with even greater ramifications.

When I first read about the Caerphilly Cohort Study, it blew me away. I couldn’t believe that I’d never heard of it before. For it suggests that making simple lifestyle changes can dramatically lower the risk of cancer, diabetes, heart attack, stroke and even dementia.

The researchers took blood samples, weighed each man and asked five simple questions. Was he a non-smoker? Did he take exercise, or walk, for at least 30 minutes a day, five days a week? Did his diet include at least three portions of fruit and vegetables a day and no more than 30 per cent fat? Did he drink less than four units of alcohol a day? And did he have a healthy body weight (a BMI of 18 to 25)?

Over the next 35 years, men who consistently answered yes to four or five of those questions had a staggeringly better quality of life than those who didn’t.²⁴ They suffered 70 per cent less from diabetes, had 60 per cent fewer heart attacks and strokes, 35 per cent less cancer²⁵ and were 60 per cent less likely to experience cognitive impairment or dementia. Elwood called this last finding ‘the real gold dust’. Even those in the healthiest groups who did get dementia got it later: its onset was delayed by six to seven years.

Remember, these results were achieved with relatively minimal change. The team wasn’t asking people to become cycling fanatics, only to start walking and cut down drinking and smoking. They even lowered the diet criteria from five vegetables or fruit a day to three after they were advised that there was no hope of getting anyone in South Wales to eat five!

‘From the results in Caerphilly,’ Elwood has said, ‘we can make a very strong challenge that if every person was urged to take up one extra healthy behaviour, and if only half did so, we’d see 12 per cent less diabetes, 6 per cent fewer heart attacks and strokes and 13 per cent less people with dementia. There would be savings in the NHS of millions.’

Those savings, however, have never materialised. Relatively few men in Elwood’s study managed to stick to four of the healthy behaviours. Thirty-five years later, looking back on his life’s work, Elwood reflected that behaviours in that part of Wales had changed little.²⁶ ‘We have found that living a healthy lifestyle is better than any pill,’ he said in 2013. But ‘people are not motivated’.

This must change. For Elwood’s findings on dementia have been reinforced by subsequent studies. In 2017, the Lancet Commission on Dementia stated, ‘there is evidence that an important fraction of dementia is preventable’ through tackling diabetes, obesity, high blood pressure, physical inactivity and smoking.²⁷

Food as Medicine

In 2017, the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (which has the marvellous acronym FINGER)²⁸ reported even more encouraging findings about the effects of lifestyle changes on the brain. Researchers recruited 1,260 people aged between 60 and 77, who were judged to be at increased risk of dementia. Half received regular health advice, the other half a comprehensive programme of healthy eating, strength training, aerobic exercise and brain training (which we will look at in Chapter 6). After two years, those who had eaten better, got more active and trained their brains scored 25 per cent better in memory and mental tests than the first group. Even more incredibly, they experienced an 83 per cent improvement in executive functioning and 150 per cent increase in mental processing speed. Intriguingly, these improvements occurred regardless of gender, education level, socioeconomic status, blood pressure or cholesterol levels.

Diet was a key part of FINGER. At the start of the study, participants deemed to be overweight were advised to lose between 5 and 10 per cent of their body weight by reducing the number of calories they consumed. Next, they were instructed to eat lots of fruit and vegetables, to consume fish at least twice a week, to choose wholegrain cereal products over refined ones and to use vegetable margarine or rapeseed oil instead of butter. They were also asked to limit their sugar intake to a maximum of 50g per day and to limit rich dairy and meat foods.

This kind of ‘Nordic’ or ‘Mediterranean’ style diet broadly reflects the plant-based, high-fibre food consumed in the Blue Zones. These diets are achievable for middle-income people without having to visit bizarre shops or spend a fortune on the latest fad.

Embarking on regimes which make you feel like a failure is just discouraging but a good basic rule is that what’s good for the heart is generally good for the brain. That means eating oodles of vegetables and fruit, plenty of fibre and avoiding processed foods as much as possible. It also means trying to eat in moderation and burn more calories than we consume.

The problem is that these messages aren’t landing. The Lancet Commission forecasts that increasing mid-life rates of obesity will lead to a 19 per cent increase in dementia in China and a 9 per cent increase in the US by 2030.²⁹ That is tragic.

We Are Our Own Worst Enemies

Professor Andrea Maier, geriatrician at the University of Melbourne, Australia, has put it wonderfully bluntly: ‘We are very lazy, we are a very lazy species and we just have to overcome that.’ She states there are three main reasons why two people can look very different from each other at the age of 50. These are: first, their levels of physical activity; second, whether they smoke; and third, their diet.

Smoking rates are falling, of course. But even as we are vanquishing smoking, obesity is rising to take its place.

My mother could have drawn the chart below. A chain smoker from the age of 14, she took up cigarettes as an act of rebellion at her American convent school. She didn’t give up until she was 70, when her arteries got so clogged that she had a mini stroke. It was a dreadful struggle for her to give up cigarettes, even with the help of nicotine patches. She immediately began gorging on chocolate, put on two stone and lost the perfect figure of which she’d been so proud. She became diabetic and later developed vascular dementia. I couldn’t help thinking, after her final, fatal heart attack, that she might have been happier staying on the fags. She existed almost entirely on ready meals after she left my father – she said she never wanted to cook for anyone again. And she never took any exercise: for most of her generation it was simply not on their horizon.

To start with, my mother didn’t really notice what was happening. As it becomes normal to be fat, people who see others the same size as them may not even notice. The psychological tendency to ‘anchor’ to those around us is very strong: in one study of 3,000 parents, a third did not even recognise that their own children were obese or overweight.³⁰

A vociferous lobby insists that obesity is genetic, but my mother came from a line of beanpoles. Look at any map showing the spread of the disease. It’s simply not possible that an epidemic like this could be genetic, eating its way through every US state, English counties and regions of Mexico. Genes do ‘load the gun’, making some people struggle harder to resist food and to manage their weight. But it is environment – diet and sedentary lifestyles – which ‘pulls the trigger’.

One in four adults in the UK, and four in ten in the US, are now clinically obese. Britons have the highest average body mass index in Western Europe.³¹ That’s because we are eating more calories than we burn. The average American’s total calorie intake grew from 2,109 calories in 1970 to 2,568 calories in 2010³² – the equivalent of eating an extra steak sandwich every day. Few people are exercising enough to compensate, especially as they drive more.

Some experts now think diet is actually less important than car ownership. In 1949, 34 per cent of miles in the UK travelled using a mechanical mode were made by bicycle; today, only 1–2 per cent are.³³ There is a stunning correlation between driving more miles and getting fatter – with a six-year time lag.³⁴

Obesity Is Making People Old Before Their Time

Extreme obesity can knock eight years off your life, according to one Canadian study. But even being overweight has a clear impact on how we age. One study found that obese people had substantially less white matter in their brains than leaner people. While our brains naturally shrink with age, the brains of the obese people were found to have a comparable white matter volume to a lean person 10 years their senior.³⁵ The impact on cognitive function is not known, but it’s unlikely to be good.

Obesity is the main cause of type 2 diabetes, which is most prevalent in older people. The number of Brits with type 2 diabetes has doubled in 20 years³⁶ and it now accounts for almost 9 per cent of the annual NHS budget. A third of Americans over 65 now have type 2 diabetes.³⁷ The consequences can be really nasty: blurred vision, sores which won’t heal, even toe, foot and leg amputations.

Type 2 diabetes develops when our bodies consume so many carbohydrates that the pancreas ceases to release the right amounts of the hormone insulin into the blood, to regulate the glucose that gives us energy. Our systems are overwhelmed and they fail.

People who head into their sixties obese are storing up real trouble in Extra Time. Doctors are wary of interfering, because they feel that what we eat is a ‘lifestyle choice’. Personally, I’m not so sure how much of a choice it is. Public health agencies have spent decades exhorting people to lose weight with almost no effect. I have become convinced that one reason we find it so hard to lose weight is that junk food – especially sugar – is addictive.

The Story of the Sugar Tax

When I served on the board of the Care Quality Commission, the national regulator for hospitals, the scourge of obesity was everywhere. Hospitals were having to reinforce beds for super-sized patients. Doctors were refusing knee replacements to people who were so overweight they feared the replacements would buckle under the strain. Some of those people became less active because their joints hurt and so gained even more weight. It was a terrible vicious cycle.

Around the same time I watched a talk by the American paediatric endocrinologist Professor Robert Lustig.³⁸ He argues that sugar is the main cause of obesity, because sugar is as addictive as nicotine and switches on the same hormonal pathways which reward behaviour. Low blood sugar affects mood, concentration and the ability to inhibit impulse. Eating or drinking something sugary reverses the effect, but if the pattern is repeated for long enough, it results in insulin resistance, type 2 diabetes, heart disease and obesity. Professor Lustig believes that it is not possible for most people to quit through willpower because that has been eroded by the cycle of craving.

My mother’s switch from nicotine to sugar made Lustig’s narrative especially compelling for me: she simply replaced one addiction with another. And it chimed with my own experience. Battling exhaustion after my third child, and sitting opposite a fellow columnist who practically mainlined Coca-Cola, I fell into the habit of needing a Coke and chocolate bar before every deadline. Since I was filing copy almost every day, as a Times leader writer, my consumption of sugar was considerable. And pretty soon the chocolate bar was no longer a single small, elegant Green & Black’s, but a string of Yorkie bars.

This kind of ‘mindless eating’ has been brought to life, hilariously and poignantly, in experiments by Brian Wansink of Cornell University. In one, he gave stale popcorn to two groups of cinemagoers.³⁹ One group got big buckets, the other got giant buckets so large that researchers assumed no one would finish them. When the movie ended, the people with giant buckets had scoured them clean – they’d consumed 50 per cent more popcorn than the others. When told this, most were astonished.

For decades, we were warned off saturated fat. A profitable industry grew up selling ‘low-fat’ processed foods. But these are a con. To make them tasty, manufacturers stuff them with carbohydrates and sugar. These create spikes in blood-sugar levels, which lead to cravings when blood sugar falls, along with the brain’s chemical messenger, dopamine. Dopamine gives pleasure, but also regulates our self-control. So Big Food offering low-fat cakes is the equivalent of Big Tobacco offering low-tar cigarettes: they make us feel better about ourselves, while keeping us hooked.

I hope that doesn’t sound hysterical. In 2015, there was a mortifying moment when I was called a ‘health fascist’ by one of the prime minister’s other advisers. We had just come out of his office in Downing Street, where I had been arguing that we should tax sugary drinks. I was taken aback to hear myself described as fascist. But I believed we could no longer rely on exhortation to stem the obesity epidemic – we needed manufacturers to change their ingredients.

In 2016, the UK government announced that it would levy a tax on sugary drinks to tackle obesity. By the time the levy came into force two years later, most brands had already done what we had hoped they would: reformulate to avoid the tax, thus withdrawing substantial amounts of sugar from the supermarket shelves.⁴⁰ While a few customers have complained about taste – and Coca-Cola has refused to dilute its legendary Classic – many are switching to low-sugar products. This suggests that relatively small signals can change markets.

Reformulating food is much more complicated for the obvious reason that processed foods contain far more ingredients than drinks (if you remove all the sugar from a cake, it will simply collapse and look like a soufflé). But the UK government has already had some success in working with manufacturers to remove salt from processed foods. The same could be done for sugar — with the right combination of goodwill and political drive.