Dr Andrew Jenkinson talks to Alice Ball about the complexities of weight-loss and how he hopes the pandemic inspires a major public health campaign on obesity.

The following is extracted from the Summer 2020 issue of Optimum Nutrition.


When we meet over a video call, Dr Andrew Jenkinson, author of Why We Eat (Too Much): The New Science of Appetite, is on his day off as a bariatric and general surgeon at University London College Hospital.

With the UK in the midst of lockdown, obesity is in the news as one of the risk factors for severe COVID-19.

According to NHS figures, 64 per cent of adults in England alone are overweight or obese, and 29 per cent are obese. However, obesity can be a difficult subject to discuss.

“At the moment, the perception of anyone who’s fat is that it’s their choice,” says Jenkinson.

It is not a view that he holds, despite having performed weight-loss surgery on more than 3,000 patients over two decades.

Not only are there some people who are genetically predisposed to gaining weight more easily, he points out, but he is also critical of the western diet.

“A western diet causes a population to become fat and have cardiovascular disease,” he says. “That is then a serious risk for having complications from coronavirus.”

For anyone who wants to lose weight, Jenkinson does not believe that going on a diet is the answer. He isn’t swift to recommend bariatric surgery either.


the more diets you’ve been on, the higher your weight set-point will rise and the slower your metabolism will become, as your body fights to protect itself from future ‘famine’


Why diets fail

Published in January 2020, his book explores the concept of weight set-point and why this causes diets to fail.

First proposed by researchers in America, the concept of a weight set-point suggests that the body is programmed to maintain a weight range — and will fight to do so.

However, Jenkinson says this description of weight set-point was “quite simplified” and didn’t fit with real life.

His experience of patients, along with research into the relationship between the gut and the brain being carried out by colleagues at University London College Hospital, led him to expand on the idea.

“There is a homeostasis or a negative feedback,” he says. “The body can increase or decrease its energy expenditure depending on how much excess fat or excess energy storage you’ve got.”

What this means, he explains, is that the more diets you’ve been on, the higher your weight set-point will rise and the slower your metabolism will become, as your body fights to protect itself from future ‘famine’.

Essentially, says Jenkinson, dieting is counterproductive to weight-loss. It’s this knowledge, he says, that gave him a new-found empathy when interacting with clients.

Now he is a “total geek” about appetite and metabolism, having spent five years researching everything he could.

Do doctors learn about food?

Yet when Jenkinson started out as a doctor, he had no interest in obesity and it wasn’t a conscious decision to go into bariatric surgery.

“When I was at medical school, obesity wasn’t a major problem and my interest in diet and nutrition was zero. I guess you sort of fall into things.”

He recalls receiving “maybe an hour’s worth” of lecture time on weight regulation while studying at Southampton Medical School.

“Medics aren’t taught much about it,” he says. “We look at different systems such as the respiratory breathing system and the urinary system, but we don’t study the weight regulation system.”


You can’t expect patients to understand it if doctors don’t understand it themselves


He admits that in his first few years as a bariatric surgeon, he was prejudiced towards his patients’ problems.

“I think I had a very similar preconception to most people in society,” he says. “I was quite judgemental before the penny dropped.”

As months and years passed, however, his outpatient clinic became increasingly swamped with patients telling a similar tale: they’d tried to lose weight, but every time they did the weight crept back on — and then some.

“When you’re hearing these stories all the time, you start to think that maybe there’s something they’re saying that we don’t understand.”

How to lose weight

What didn’t make sense to Jenkinson was that if the dogma of calories in, calories out was correct, people should have actually been much bigger.

“Obviously something is happening because the figures don’t add up,” he says.

“How can people eat so much and not put weight on? It’s the same when people starve themselves and don’t lose as much weight as they want.”

He also believes that elements of the western diet — including high levels of omega-6 and refined grains — contribute to a gradual elevation of the weight set-point.

Despite the many factors that contribute to obesity, however, Jenkinson believes that it is possible to escape its trap by gradually lowering the weight set-point.

The final chapter of his book sets out a blueprint for a healthier weight, aiming to reach people stuck in an endless cycle of dieting and to catch them before they consider surgery.

Although those that get bariatric surgery see drastic life improvements afterwards, he says, changes in medical training are vital to prevent people from reaching that stage in the first place.

“You can’t expect patients to understand it if doctors don’t understand it themselves.”

He also hopes to deliver more conferences to medical professionals and, after lockdown, his first TEDx talk.

In the meantime, Jenkinson hopes that the pandemic will inspire a change.


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