Cookery lessons at school is a good starting point against obesity, writes PROFESSOR ROB GALLOWAY 

As an emergency room physician, I spend most of my time acting as a plaster on society’s problems.

Smoking, alcohol, drugs, loneliness, lack of exercise and poverty are the underlying causes of most of the illnesses and injuries that bring my patients to the emergency room – but obesity tops that list.

It’s amazing even to me as a doctor how many knock-on-malign consequences there are from obesity. One of the patients I saw recently personified this.

A man in his early 40s, he had been brought in because he had an infection spreading across the skin – a condition called cellulitis – and he developed sepsis, a life-threatening condition.

But below that was his weight: he weighed more than 28 st (180 kg).

The pressure on his heart was so great that he had high blood pressure (for which he took three different kinds of medication every day); he had type 2 diabetes and high cholesterol. Six months ago he had a lung clot that nearly killed him.

In total, he required nine medications to manage the day-to-day effects of his obesity, as well as regular hospital and GP appointments.

A few months ago he had to give up his job as a security guard because he had trouble walking, and now he was housebound*.

Obesity had turned this once healthy, jovial man into someone who struggled with depression and was at risk of an early end.

On the day I saw him, he required intravenous antibiotics and had to be admitted to the hospital. The infection in his leg had started with a small cut, caused by a lack of sensation in his feet from diabetes. His obesity subsequently affected his ability to fight the infection.

His admission will be recorded due to sepsis, but the real cause was obesity. This story isn’t unique either: I estimate obesity is a contributing factor to a third of admissions — and is implicated in conditions ranging from dementia to strokes and heart attacks.

Such patients need help, which is why I was delighted to hear last month that the National Institute for Health and Care Excellence (NICE) has recommended that a breakthrough weight-loss drug – semaglutide – be made more widely available on the NHS.

It is sold under the brand name Wegovy and may be offered once a week for two years through specialized weight loss centers to people with a body mass index (BMI) of 35 and at least one weight-related condition, such as high blood pressure (or, exceptionally, for people with a BMI of 30-34.9).

The evidence behind this treatment, first published in 2021 in the New England Journal of Medicine, is compelling.

Those who received weekly semaglutide injections lost 14.9 percent of their weight over 68 weeks, compared to 2.4 percent in those who received lifestyle advice alone.

Given that two-thirds of Britons are overweight and nearly a third of us are classified as obese, many commentators welcomed the drug’s wider adoption in the NHS as an outcome.

But is semaglutide the miracle we need, or are there simpler solutions?

Semaglutide activates a receptor in the gut called glucagon-like peptide-1 that slows stomach emptying after eating, helping you feel full and consume fewer calories.

However, there are problems with it: it has to be injected, is very expensive, and once treatment stops, some of the weight comes back.

In addition, it must be taught in specialized institutions, which are few. But most importantly, while the drug helps, we are providing treatment for a largely preventable condition. And surely our greatest efforts should be aimed at prevention rather than cure?

The problem is that it’s not that easy. Most people don’t even seem to know what to eat. Instead of asking why some of us are obese, a better question is why aren’t we all obese?

In fact, the craving for unhealthy, highly processed, high-fat, and high-sugar foods is ingrained in our DNA. That craving some of us have for chocolate is not gluttony but an evolutionarily beneficial trait. (Saving calories made sense thousands of years ago when there would be days without food.)

With so much availability of these foods, it’s no wonder there’s an obesity epidemic.

And while doctors used to believe that if we ate more than we needed, we’d gain weight (and if we burned more calories than we ate, we’d lose weight)—we now know that’s a gross oversimplification.

One of the main reasons we gain weight is in response to blood sugar spikes. High levels of sugar in the body cause a spike in the secretion of the hormone insulin, which encourages the body to store sugars as fat.

But there are other factors at work. First, not all calories are the same. A highly processed cookie is quickly broken down by the body, creating sugar spikes that are converted to fat by insulin.

But a fiber-rich piece of fruit is broken down more slowly; the sugars are absorbed less easily and are not converted into fat. So the same number of calories but a completely different result.

How food is prepared is also important. Eating fruit is healthy, but fruit juices are much less so. Squeeze some oranges and you don’t have to expend energy breaking down the fibrous components of the orange and all the sugars are released at once – so sugar levels rise, insulin rises and sugars are converted to fat.

Then there’s what makes us feel full. Eating protein and healthy fats like nuts and avocados is more filling than eating highly processed foods like cakes and cookies.

And there are other factors to consider: lack of sleep, for example, causes us to eat more.

Exercise is very good for you and will help you to keep losing weight – but without a change of diet it is difficult to lose weight by exercise alone. Instead of increasing your total energy expenditure, the body simply uses the same amount of available energy more efficiently.

Given the knowledge we now have about the preventable causes of obesity, it seems tragic that we still place so much hope in an injection that may or may not have long-term benefits.

Think about how my patient turned 28.

He never learned how to cook, so he doesn’t bother. He drove to work, because there was no public transport. At work, the available food came from a vending machine: chocolate, chips and fizzy drinks, with no salads, vegetables or fruit. At home, watching TV, he drank sleep-disrupting, high-calorie beer.

So what’s the answer? Semaglutide injections can help him lose some weight temporarily; but as soon as he no longer has them, he can gain weight again.

We must first of all prevent people from becoming so dangerously overweight. We need to ensure cooking classes are available in schools and workplaces have access to healthy food.

We should tax unhealthy fast food (this worked with smoking) and subsidize healthy food; plan cities with fewer fast food outlets and where walking is the default mode of transportation; and provide better access to sports clubs and gyms.

We also need more access to dietitians and clinics for those who are becoming obese.

Importantly, healthcare professionals must have the knowledge and confidence to be honest with patients about the changes they can make to live healthier lives.

Because when someone reaches my patient’s size, it’s incredibly difficult to lose significant amounts of weight without the expertise of health professionals.

Making these necessary societal and personal changes in how we live our lives and what we eat is the best recipe for tackling the obesity epidemic – more than any injection.

Twitter: @drobgalloway

* Some of my patient’s data has been changed for confidentiality.