DR PHILIPPA KAYE: Diets fail because obesity is a disease and only way to beat it is with treatment

The patient in my treatment room – a busy working mother-of-two in her 40s, let’s call her Kelly – seemed desperate.

As her GP, I’d seen her a fair few times before – after the birth of both her boys, and every now and then for her own health problems. This time, however, she wasn’t herself at all.

Tearfully, she explained, it was her weight. Recently she’d started a new job in retail, and had been told there wasn’t a uniform large enough to fit her.

‘I felt so ashamed and guilty,’ she admitted through sobs. ‘I’ve tried to lose weight, but I can’t.’ I have lost count of how many times patients have said those exact words to me over the past decade. Most want to know if I have any advice. The answer is yes, and for starters it’s not to go on another crash diet.

‘Obesity is a disease,’ writes Dr Philippa Kaye. ‘It’s a chronic, incurable condition that affects the brain and hormones – in children as well as adults’

But before that, I have one simple yet vital message, and it’s one every person who struggles with their weight needs to hear: This isn’t your fault. You’re not greedy or lazy. Your weight is not the result of not exercising enough, or dieting hard enough, or anything else that people might have told you.

The reason you’re struggling is because obesity is a disease. It’s a chronic, incurable condition that affects the brain and hormones – in children as well as adults. The degree to which an individual is affected is largely down to genetics – although, of course, eating patterns, sleep, physical activity, socioeconomic status and certain medications also play a role.

Overeating is the main symptom. And only a minority of patients with obesity – you didn’t misread that, as obesity is a disease it’s correct to refer someone as ‘having’ obesity – will manage to lose weight, and keep it off, with lifestyle changes alone. The most enlightened medical thinking is that most require treatment, including psychological therapy, medication – which may well be for life – or possibly surgery.

American, Canadian and Portuguese health authorities, as well as the World Health Organisation, all now recognise that obesity is a disease in its own right.

Dr Phillipa Kaye (pictured) is a GP on the front line of the obesity crisis

Dr Phillipa Kaye (pictured) is a GP on the front line of the obesity crisis

And I believe strongly that we also need to, not only because it might go some way to removing both the stigma and blame associated with the condition, but it will make a huge difference to the help patients are given on the NHS.

I know some will think that by classifying obesity as a disease we are medicalising something that’s a variant of the normal human condition. But as Professor Alex Miras, an expert in obesity and metabolism at Ulster University and Imperial College London, says: ‘About 25 to 30 per cent of the population have high blood pressure, and we don’t debate putting them on medication to control that.

‘If someone has high cholesterol, putting them at risk of a heart attack or stroke, we offer medication to control that and reduce their risk.

‘Why should treating obesity be seen as any different?’

I couldn’t agree more.

At present, just over a quarter of UK adults fall into the medically defined category of obesity. That means their body mass index (BMI) score – a ratio of height to weight – is 30 or more. A further 32 per cent of women and 43 per cent of men are overweight. This equates to about 35 million people.

Excess body fat is a concern, as it increases the risks of many illnesses. By the end of the decade, it is projected that one in ten adults will suffer type 2 diabetes, when blood sugar becomes abnormally raised and begins to cause widespread damage in the body.


In 1980, roughly six per cent of men and nine per cent of women in England were obese. In 2019, it was just under a third of both men and women.

There are 2.3 million people with coronary heart disease – again, intrinsically linked to obesity – and numbers are steadily rising. The problem, which involves blocked arteries, kills 180 people in the UK every day. And more than one in 20 cancer cases are associated with excess weight.

I say this not to shame anyone, but I know the misery these problems – and obesity itself – cause and I want to see things improve. And if, by treating obesity with medication or surgery, we prevent some of these other illnesses, there will also be a huge benefit in freeing up NHS resources.

Before we go any further, let’s get the counter- arguments out of the way: A cousin/friend/partner managed to lose weight on a diet.

If it worked for them, that is great. But research suggests that 80 per cent of those who achieve significant weight loss fail to maintain it for more than a year. One analysis suggested dieters regain more than what they lose within two years, even with intensive support from healthcare professionals.

Are they all simply weak-willed?

From my own experience as a doctor, sitting face-to-face with patients like Kelly, I’d say not. Every one of my patients with obesity or overweight knows it, and has tried everything they can.

Another thing I often hear: People get fat because they eat junk, end of story.

Well, no. It’s true that food has changed dramatically over the past 100 years, due to mass production – which has made it ever more affordable.

And many of these ultra-processed products are also high in calories, fat, salt and sugar, which, when eaten to excess, contribute to weight gain.

Some research even suggests these foods can impact on the hormones which make us feel hungry and full, meaning we eat more of them than perhaps we should.

Everywhere you look there are takeaways and fast food, supersized snacks, sugary drinks and buy-one-get-one-free supermarket offers on cake.

But we all live in this ‘obesogenic environment’, and only some of us have obesity. So what else is going on?

Well, for starters, decades of research has shown that whether or not we develop obesity is largely down to our genes.

At present, just over a quarter of UK adults fall into the medically defined category of obesity

At present, just over a quarter of UK adults fall into the medically defined category of obesity

In the 1970s there were compelling studies involving identical twins, who lived apart but share almost exactly the same DNA. Despite having grown up in different places, and sometimes different countries, they were usually the same weight, leading scientists to suspect biology, rather than environment, were major drivers.

More recently, scientists have identified hundreds of genes that increase the risk of obesity.

Prof Miras explains that mutations in these genes lead to changes in the parts of the brain that regulate appetite.

‘They mean a person has ‘higher’ hunger than normal, and ‘lower’ feelings of fullness, so will ultimately consume more calories than they need and gain weight. This is the disease of obesity, which causes overeating.’

It’s not fully understood why appetite genes become faulty, but the more of these genes a person has, the greater their weight is likely to be. This certainly chimes with what patients with obesity tell me: they talk of feeling hungry more than their friends, that they eat faster than others and feel less satisfied afterwards, that they don’t ever feel full.

As one of Prof Miras’s patients, Nikita, told us: ‘I’ve always been able to eat a lot. I can easily have a whole large pizza to myself. And when I was younger, it didn’t matter – I stayed slim.

‘But after I had my son I carried on eating a lot, and began to put on more and more weight.’


Vietnam has one of the world’s lowest rates of obesity – roughly two per cent of adults compared with 40 per cent of American adults.

The 38-year-old mother-of-one continues: ‘I’ve tried dieting, going low-carb, and cutting out sugary drinks. But I found that only made me crave food more.

‘I’d tell myself: no biscuits. I’d last a few days then end up demolishing three packets in one go.

‘Being overweight is horrible. When I look in the mirror, I don’t recognise myself.

‘I have breathing problems and joint problems.

‘I used to feel confident but I just want to hide away now. I rarely go out, and feel miserable all the time, which just makes me want to eat more. It’s a vicious cycle.’

Nikita, who is 5ft 3in and weighs almost 15st – giving her a BMI of 37 – is on the waiting list for weight-loss surgery, which she hopes will end her struggle.

She is set to have a gastric bypass, in which the stomach is cut and stitched in such a way that it becomes a tube.

It was previously believed that these operations worked by simply by reducing the amount of food that can be eaten, but experts now believe they halt the over-production of hunger hormones, meaning patients don’t have the same urges to eat. While surgery might seem drastic, for patients suffering disabling health problems, it can be lifesaving.

In addition, there is a new class of remarkably effective weight-loss drugs.

They work by mimicking the hormone glucagon-like peptide-1 (GLP-1), which is released after eating and leads to feelings of being full. Patients inject themselves and report that, while on the treatment, they are less hungry and sometimes even forget to eat.

In trials of one of these drugs, semaglutide, participants lost on average 16 per cent of their weight after a year of treatment.

Some received intensive diet support, while others were given none – but both groups lost the same amount of weight.

Another arm of the trial involved switching some patients who had been on semaglutide for six months to a dummy jab without them knowing. They reported feeling hungrier and eating more, and regained much of the weight they had lost.

Crucially, experts say that the success of semaglutide and similar drugs further supports the idea that obesity is a disease: that over-production of hunger hormones is what causes weight gain, and tackling that problem specifically can lead to recovery.

Everywhere you look there are takeaways and fast food, supersized snacks, sugary drinks and buy-one-get-one-free supermarket offers on cake. But we all live in this 'obesogenic environment', and only some of us have obesity. So what else is going on?

Everywhere you look there are takeaways and fast food, supersized snacks, sugary drinks and buy-one-get-one-free supermarket offers on cake. But we all live in this ‘obesogenic environment’, and only some of us have obesity. So what else is going on?

Semaglutide and similar drugs aren’t that easy to get on the NHS. Patients must have a BMI of 30 or more, suffer related health problems and have tried other non-drug methods to lose weight.

But later this year, research will show if the weight loss brought about by semaglutide also prevents heart attacks.

If it does provide protection, there will be a compelling economic argument for the NHS to provide it to millions more Britons in the same way that we prescribe statins and blood-pressure medication.

Aside from surgery and drug treatment, there is also cognitive behavioural therapy (CBT) – a kind of psychotherapy – which has also shown to have some success in helping people tackle other factors that they feel cause them to over-eat, such as stress and anxiety.

Of course, treatment is one thing – but prevention, as they say, is better than a cure. And this will be far more complex.

As of last year, ten per cent of children aged four to five were classified as obese. At age ten to 11, this figure rose to 23 per cent.

Research shows that children with obesity are likely to grow up to be adults with obesity. However, children lose weight through lifestyle changes more easily than adults – because eating habits caused by faulty genes are less ingrained.

If behavioural approaches don’t work, another GLP-1 drug, liraglutide, is licensed for patients as young as 12.

While adults who qualify for these drugs are likely to need treatment for life, or risk putting on weight again, early intervention might lead to a more lasting effect in teens – children may be able to stop taking the medication and maintain a healthy weight.

None of this means making healthy food choices and regular exercise aren’t still vital.

I have no doubt what I’m saying will cause debate. So I’ll leave you with my patient Kelly, who I referred to an NHS obesity clinic. She was prescribed a GLP-1 inhibitor and, a year on, she is transformed. When I see her she talks of a sense of relief – that she is no longer a slave to her appetite. She no longer feels ashamed or guilty or depressed.

And she has lost a significant amount of weight, reducing her risk of a range of serious health problems. As her doctor, what more could I want?

Low-risk diet drugs the NHS has to take seriously



Diet pills have had a bad rap – justifiably, I’d say. In the 1960s there were the ‘miracle’ appetite suppressants fenfluramine and phentermine, taken by millions of slimmers around the world.

The drugs turned out to cause heart valve damage, which is sort of unsurprising as they are amphetamines by another name.

Barney Calman, Health Editor for The Mail on Sunday

Barney Calman, Health Editor for The Mail on Sunday

More recently there was sibutramine, which damaged the heart AND triggered psychosis and suicidal thoughts. Oh, and rimonabant. It helped people lose a bit of weight, but left many with depression.

Orlistat, which is NHS approved, doesn’t dampen the desire to eat. Instead it works by blocking the absorption of fat in the gut, which means that you excrete it… sometimes uncontrollably. Lovely. But the advent of new GLP-1 obesity treatment drugs has been a game-changer. They seem low risk – and they really work. This year, we’ll learn if those who lose weight on semaglutide are less likely to have a heart attack or stroke.

If so, the jabs might become as ubiquitous as cholesterol-lowering statins, given to anyone at risk of developing an obesity-related illness.

That’s a lot of people. And in the pipeline there is a powerful drug, CagriSema, which leads to even greater weight loss, faster.

Is obesity a disease? It’s a persuasive theory.

The important thing is that if the new medicines can help tackle the obesity crisis then NHS chiefs must take them seriously, look at the scientific evidence and stop peddling tokenistic initiatives such as impossible-to-stick-to diets and putting calories on menus – both of which do very little other than make people feel bad, and, as a result, eat more in the long term.

Author: Wayne Evans