Paul Cherry was in his mid-40s when he first felt unwell enough to see his GP. ‘I was so tired, I was sleeping all the time and feeling unusually snappy,’ recalls the father of two. ‘It hurt to pee as well.’

Paul was diagnosed with type 2 ­diabetes and initially put on ­metformin to lower his blood sugar levels, then later he began taking insulin daily. At the same time, he was also ­diagnosed with NAFLD – non-­alcoholic fatty liver disease, a build-up of fat in the liver that is a common precursor to cirrhosis (liver scarring).

As the name suggests, NAFLD is not related to alcohol intake: risk factors include a family history of fatty liver and having type 2 diabetes. It usually affects those who are overweight, although liver specialists say people of normal weight can also develop it – known as ‘lean’ NAFLD.

Although around a stone overweight at the time, Paul wasn’t obese. Instead, his doctors believe he developed type 2 diabetes due to a diet laden with junk food and sugar – NAFLD followed as his blood sugar ­levels became ­chronically high, damaging his liver.

Yet in the nine years following his diagnosis, Paul didn’t make the lifestyle changes doctors ­recommended – including exercising more and cutting out cakes, sweets and fizzy drinks.

As Paul, 56, admits: ‘I was partial to a doner kebab and I was drinking up to three big bottles of fizzy drink a day, even though I’d been told it was bad for my liver.

‘While I tried to eat more healthily, I didn’t take it seriously enough, ­possibly as I wasn’t really ­overweight. I just wasn’t scared enough – but I should have been,’ says Paul, a driver with a fleet support company, who lives in Stevenage, Hertfordshire, with his wife, Kim, 56, a classroom assistant.

But his fizzy drink habit was one of the ­reasons he ended up so dangerously ill that he needed an emergency liver transplant last year.

One problem is that you can have NAFLD mildly and not know it – it can then gradually worsen until the liver becomes so inflamed and scarred, it results in cirrhosis (with the symptoms, such as a dull ache in the top right of the tummy, extreme tiredness, weight loss and weakness, sometimes coming on suddenly).

It’s also possible to have ‘a ­perfectly normal body mass index but a fatty liver’, explains Professor ­Jonathan Fallowfield, an honorary ­consultant hepatologist at the The Royal Infirmary of Edinburgh and a spokesman for the British Liver Trust.

Such patients are often referred to as ‘lean on the outside, but fat on the inside: with fat wrapped around the organs, including the liver’, he says.

Paul had been around 16st for most of his adult life, but didn’t look overweight due to his height – 6ft 2in. As a relatively trim-­looking gym-goer and lifelong non-drinker, he mistakenly thought he’d be the last person to develop liver ­disease.

His story is not unique. As a nation we’re not looking after our livers – liver disease has risen four-fold in the past 50 years, according to the British Liver Trust. It’s the only major disease where death rates are rising.

The liver is the body’s biggest internal organ and its job is to break down ­toxins. But if its function is ­compromised, these build up in the blood, leading to a host of ­problems including ­mental ­confusion. The liver also stores glycogen, which our muscles use as fuel (which is why liver damage can cause muscle weakness).

Problems start when fat ­accumulates in the liver and then over time causes damage. In ­serious cases, this can progress to ­cirrhosis – cases of ­the condition increased by 21 per cent between 2019 and 2021 alone.

Yet caught early, liver damage can be reversed. While it’s known that being overweight is a risk ­factor, studies show ‘poor diet – including ultra-processed foods –also increase the ­risk, even for those who are slimmer’, the British Liver Trust told Good Health.

As Professor Fallowfield ex­plains, a range of ‘dietary insults’ can affect the liver, ­including high sugar ­consumption, which not only directly ­contributes to obesity but also excess blood glucose, which can damage blood vessels and organs.

Trying to protect us, the body removes the sugar, ­storing it as visceral fat – a ­particularly ­dangerous type that collects around internal organs.

Professor Fallowfield explains that visceral fat ‘is associated with higher levels of inflammation, insulin resistance [a precursor to type 2 diabetes] and liver ­scarring’. ‘But what is now becoming clear is that you don’t have to drink lots of alcohol or be obese to get liver damage – up to 20 per cent of people with a normal BMI have NAFLD,’ he says.

And it seems that the number of ‘lean’ people with fatty liver is on the rise, according to a 2023 US study that identified a ‘subset of individuals... known to have lean NAFLD... which is increasingly prevalent’.

There’s currently no approved treatment for an unhealthy liver, says Professor Fallowfield. While so-called liver ­supplements such as milk thistle and turmeric will ‘do you no harm’, he says dietary changes and regular exercise are the ‘best, in fact the only, remedy’.

He advises switching to a ­Mediterranean-style diet rich in fish, fruit and vegetables, and being as active as possible.

One ­problem, he adds, is people with lean NAFLD are not suspected of ­having fatty liver ­disease in the same way overweight patients are – this can lead to late diagnosis, when the ­disease has already ­progressed to a more severe stage.

And sometimes the ­symptoms can come on suddenly, as in Paul’s case. After his diagnosis, he saw a liver consultant twice a year and there was no change in his liver function. Then, out of the blue, in mid-2022, he became acutely ill.

He felt tired and ­irritable, ‘then I stopped eating and began to lose a lot of weight – four stone in three months. I also felt confused and had no control over my muscles.’

Paul also kept falling over – once breaking two ribs. He recalls: ‘I needed help to dress. I didn’t know what was happening to me.

‘Then, one evening in 2022, we were at home watching TV when I ­suddenly felt the most ­unbearably sharp pain in my abdomen. I was rolling around on the floor. I thought I was going to die.’

Paul was taken to hospital, where a scan revealed problems with his liver. It was so badly damaged Paul was transferred to the Royal Free Hospital in London, where ­specialists told him he needed an urgent transplant.

He says: ‘I was very frightened that I might not see my daughter married [he also has a son], or see my grandchild grow up. I tear up even now just thinking about it.’

Paul was sent home to wait for a donor liver to become available, but he continued to deteriorate.

Failing liver function meant fluid leaked out his liver veins, causing a build-up in his ­abdomen and legs; several litres had to be drained in hospital every fortnight. It was, he says, ‘a bleak, stressful time’.

His ill-health meant his driving licence was taken away, he lost his job of 28 years and doctors advised him to make a funeral plan. ‘I was on the scrapheap at 54,’ he recalls. ‘Everywhere I went I had a bag packed; in case we got the call. My wife and ­daughter and I cried most days.’

But then in May last year, on Coronation Day, he got the call: a liver had been found. He recalls tearfully: ‘I said goodbye to my wife and daughter, just in case I didn’t make it.’

The transplant was a success and Paul has since planted a tree in his garden as a memorial to his donor – he knows only that the donor was a man.

Paul counts his blessings and has transformed his diet: it’s now brown seeded bread, lean meat, pasta, and fruit and veg that he grows on his new allotment – and water instead of fizzy drinks.

He’s still a stone overweight, but feels ‘100 times better’, walks to the shops instead of driving and carefully scrutinises food labels for sugar and fat content.

‘I’m living proof that fatty liver disease can happen to non- drinkers,’ he says. ‘I still get flashbacks to when I was gravely ill. I’m never going back there.’