Obesity: tackling one of the nation’s leading causes of death

By Annabel Kartal-Allen | Published: 13-Feb-2024

Obesity affects more than one in four adults in the UK, with approximately £6.5 billion per annum being spent nationally on this preventable disease

There are many temptations made available to the public by the food industry; cheap and tasty snacks full of chemicals that fill our brains with dopamine are available on every street corner.

Sometimes we may find ourselves overindulging and thinking: “Oh, I’ll just be good for the rest of the week.” But is this damaging to our health in the long-term? Annabel Kartal-Allen spoke with Lee Humphreys, a bariatric surgeon with more than 10 years of experience in obesity healthcare, to discover the causes and effects of this widespread condition, the best ways to lose weight and how we can keep it off. 

Why and how we gain weight 

Weight gain can be instigated by a combination of factors, with a commonly discussed trigger being genetics. Mr Humphreys elaborated on this: “We need to look at weight gain in the context of evolution. If you go back hundreds of thousands of years, when we were hunter gatherers, it was never certain when your next meal would be available.

Therefore, from an evolutionary point of view, it makes no sense for it to be easy to lose weight; it would be bad for the species in periods of starvation and we would die out quickly. We’ve actually had to evolve very powerful mechanisms to conserve weight.”

“But, fast forward to where we are now; very few people have to worry about food availability. We're now living in an environment in which we’re surrounded by calorie-dense food that's readily available; but, we have these ancient genetic adaptations that mean we conserve weight, potentially leading to obesity in the long-term.”

Approximately 30% of the people that we see through the obesity service have had prior trauma, which has contributed to their obesity

Our choices and behaviours impact our weight 

From the roots of our evolutionary history to now, human health and well-being will always be significantly impacted by our behaviour and choices. Mr Humphreys acknowledges this as a significant factor in the obesity crisis too: “People get into habits that predispose them to gaining weight. It can become very difficult to break those behaviours.”

“That's not to blame people,” he adds: “A huge amount of this has to do with what we’re eating and the sorts of food that we're surrounded by. Ultra-processed foods, which are directly linked to obesity, are everywhere; even if you want to avoid them, it's often difficult to do so. 

Mental health doesn’t just affect your cognition

Mr Humphreys also stresses the importance of acknowledging the link between mental health and obesity: “The psychological aspect of obesity is particularly important. Approximately 30% of the people that we see through the Complex and Severe Obesity Service (University Hospitals Plymouth NHS Trust) have had prior trauma, which has contributed to their obesity.”

“Patients who have been through harrowing events may never have spoken about them prior to coming to a weight management programme. It’s vital to do a psychological assessment for this very reason. Some patients will need to work with psychologists regarding trauma or other triggers because, without getting to the root cause of the problem, it’s unlikely that people will make the necessary lifestyle changes for treatment success.”

The perils of dieting

It’s very common for people to begin dieting when they believe they are gaining weight. Mr Humphreys vehemently warns against this: “In the short-term, going on a diet will cause you to lose weight. Unfortunately, in this scenario, your brain is hardwired to interpret this as a period of starvation. Therefore, ancient physiological adaptations will kick in and your basal metabolic rate will go down.”

“This results in a person requiring less energy to survive than usual. As a result, hunger levels will decrease and your level of satiety will increase. You’re then using less energy; but, when you finish your diet, you will most likely go back to a standard, recommended calorie intake, which is now excessive compared with your metabolic needs. You’ll then unknowingly consume excessive calories on a daily basis.”

“It may only be 200–300 calories per day, which doesn’t sound like a huge amount. But, during the following weeks and months, that could become 1–3 kg of weight gain a year. As a result, many people suffer from insidious weight gain for decades. Diets would work if you’re able to stick to them for the rest of your life. But who wants that? Only a handful of people can make that sort of commitment.”

Discussing the “fat but fit" concept

There has been a shift in the public perception of obesity, with many advocating for body positivity and self-acceptance. The “fat but fit” concept was born on social media, bringing together people that are overweight and obese who have no diagnosed metabolic disorders.

“I don’t think anybody should be fat shamed, nor do I believe in the discrimination of overweight or obese people,” emphasises Lee. “However, the notion that you can be severely obese and metabolically healthy in the long-term is a dangerous one.”

“For example, you might observe a patient who is 25 years old — with a BMI of 40 — with no obesity related complications (such as type 2 diabetes or high blood pressure). However, if you monitor that person for a long period of time, there’s a high likelihood that those conditions will manifest themselves.” In a recent study, a group of obese but metabolically healthy individuals were followed up for 16 years; the results revealed that 53% of them developed metabolic diseases during the observation timeframe.1

Mr Lee Humphreys, Consultant Upper GI and Bariatric Surgeon,
Complex and Severe Obesity Service,
University Hospitals Plymouth NHS Trust

Mr Lee Humphreys, Consultant Upper GI and Bariatric Surgeon, Complex and Severe Obesity Service, University Hospitals Plymouth NHS Trust

BMI as an accurate weight categorisation

BMI, or body mass index, has caused significant controversy in healthcare owing to its failure to differentiate between body fat and lean muscle. Although it may not always accurately reflect a subject’s true body fat to muscle ratio, Mr Humphreys believes it still has its place as a ballpark measurement: “We know that BMI has failings. It may not always account for muscle mass in individuals, but the vast majority of the general public are not professional athletes with unusually high muscle densities. For most people, BMI is an easily calculated measure of adiposity and it correlates well. It is important, however, that patients are not diagnosed simply on a BMI calculation alone. A comprehensive medical assessment should be done on an individual basis.”

The link between obesity and major health issues

There is a significant link between obesity and heart disease, which is the most common cause of death in the UK. The association comes from the build-up of fatty tissue in the arteries supplying the heart, which can cause cardiac events or myocardial infarction. Additionally, clinical knowledge of the correlation between obesity and incidences of cancer has drastically increased during the last 20 years. There are now 13 cancers that are directly linked to obesity. Mr Humphreys comments: “The number of oncological conditions linked to obesity is gradually rising. Nearly all of the common ones — colon, breast, ovarian and prostate cancer — are all linked to obesity.”

Not only has obesity been linked to both of the most frequent causes of death in the UK, it has also been associated with neurodegenerative diseases such as Parkinson’s and cognitive decline. “There are currently growing links between dementia and obesity; it affects every organ system in the body and that’s something that gets underestimated and overlooked frequently.”

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Society’s outlook on obesity

The stigmatisation of obesity is common in many societies globally and Mr Humphreys believes a change of outlook is necessary to tackle the crisis: “We need to look at obesity as a chronic disease. Moving away from blaming individuals about being overweight and obese is so important; we know it's not their fault. Some of us are naturally more prone to it than others.”

Lee adds: “It’s a disease that will require lifelong intervention and treatment. Many countries have accepted that fact, but there’s still a long way to go. Once we do that, hopefully we will start to reduce some of the stigma and the problems that patients with obesity face in terms of getting treatment and support for their condition.”

Obesity places significant pressure on the global healthcare infrastructure, with many public systems unable to afford the costs of treating long-term complications. The risk to public wellness is also palpable, with debilitating conditions such as high blood pressure, cancer and type two diabetes often accompanying the condition.

With this knowledge, the industry must do all it can to assist those who suffer from the ill effects of obesity earlier and advocate for healthcare availability, medical solutions and accessible treatment options for those affected.


  1. https://pubmed.ncbi.nlm.nih.gov/37828801/.

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