Slim hopes: Who really benefits from the obesity wonder drugs?

Paul McNamara is a GP and Honorary clinical lecturer at the University of Glasgow

Ruth Somers is a final year medical student at the University of Glasgow

In 2022, 43% of adults worldwide were overweight, and 16% were obese.¹ The World Obesity Federation predicts that by 2035, over four billion people will be living with obesity.²  The impact on the NHS is already being felt. Obesity contributes directly to rising multimorbidity, including diabetes, cardiovascular disease, and some cancers.³ One in five women of reproductive age in the UK is obese, increasing the risk of adverse pregnancy outcomes and future chronic illness in both mother and child.⁴ Tackling obesity is has become a press public health concern.

Semaglutide, a GLP-1 receptor agonist originally licensed for glycaemic control in type 2 diabetes, has since emerged as a potential breakthrough in obesity treatment.⁶ Clinical trials have shown average weight loss of around 12kg over 68 weeks.⁷ Semaglutide works by acting on the hypothalamus to reduce appetite, delaying gastric emptying, lowering blood glucose levels, and modifying pancreatic hormone release.⁶ The SELECT trial demonstrated a reduction in the risk of major cardiovascular events among patients treated with semaglutide, even in those without diabetes.⁸

It is easy to see the appeal. Compared to lifestyle modification alone, these drugs appear transformative. But how wonderful is this so-called “wonder drug”?

A Slim Solution With a Heavy Price

GLP-1 agonists have gained popularity rapidly, in part due to endorsement by celebrities, politicians and public figures.⁶ However, the financial cost is substantial. In England, widespread adoption could double the annual NHS prescription budget.⁷ It is estimated that prescribing injectable weight loss medication costs around £3,000 per patient per year.⁹ On the other hand, obesity-related illness costs the NHS an estimated £6.5 billion annually — and rising.⁵

Despite the potential for long-term savings, access remains limited. Over the next three years, only 220,000 people in England are expected to receive semaglutide, out of 3.4 million who are eligible.⁹ This discrepancy forces many to turn to private care. The result is a growing two-tier system, where those with financial means access effective treatments while others are left behind.

This is already becoming a reality. It reflects the inverse care law — those who most need care are often least likely to receive it.¹⁰ Since obesity is linked to socioeconomic disparities, the concern is that these medications, while clinically effective, risk deepening health inequalities.¹¹

This is particularly evident in practices like mine, serving socioeconomically deprived communities. Food insecurity, overcrowded housing and limited access to safe outdoor space are all too common. The obesogenic environment is not abstract — it is the lived reality of many patients.¹

The Food Foundation has shown that the poorest fifth of UK households would need to spend between 45–70% of their disposable income to afford a healthy diet.¹² Access to good nutrition, safe walking routes and exercise facilities should not be a privilege — yet for many, they are entirely out of reach.

Shared Care, Split Responsibility

While GLP-1 drugs hold promise, they are not without risk. The BNF lists 24 medicines that interact with semaglutide.¹³ It has also been shown to reduce the effectiveness of oral contraceptives, prompting updated MHRA advice recommending additional non-oral contraception during treatment.¹⁴ ¹⁵ Other adverse effects include pancreatitis, gallstones, stomach paralysis, and potential long-term risks such as thyroid tumours and renal impairment.¹⁶ Rebound weight gain is also common after treatment is stopped.⁶

In Scotland, there are currently no formal shared-care pathways for privately prescribed weight loss medications (to the best our knowledge). Nonetheless, GPs are frequently asked to take over prescribing or monitoring responsibilities from private providers — often without a full clinical handover. it is possible to issue prescriptions following only minimal assessment or follow-up.

This raises fundamental questions about safety, governance and medicolegal accountability. If a patient experiences an adverse outcome, who is responsible? Can a GP be expected to monitor treatment they did not initiate? This emerging model of informal, unfunded shared care is neither safe nor sustainable.

General practice is already under immense strain. We cannot absorb further responsibility without appropriate systems, support and resourcing.¹⁷

The Bigger Picture

Drugs like semaglutide can support weight loss and may reduce the burden of obesity-related disease. But obesity is a complex, multifactorial condition.³ Pharmacological treatment must be embedded within a broader strategy — including dietary advice, behavioural support, and addressing the wider determinants of health.⁶ Used appropriately, GLP-1 agonists can be part of the solution. But if we allow them to be framed as the solution, we risk oversimplifying a much deeper problem. Until we address poverty, food inequality and the wider systemic barriers to good health, we are not treating the cause — only the symptoms.

GLP-1 agonists can support individuals in managing obesity, but they are not a substitute for public health investment. Real progress will require policies that tackle poverty, reform the food environment, and make healthy choices accessible to all.

Deputy Editor’s note – see also:

• https://bjgplife.com/are-glp-1-agonists-the-answer-to-our-obesity-epidemic/
• https://bjgplife.com/semaglutide/
• https://bjgplife.com/obesitys-hidden-drivers-suggest-that-drugs-need-not-be-the-answer/

References

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Featured image by Diana Polekhina on Unsplash