Science editor Florence Lakin discusses what she learnt about obesity and Ozempic at Giles Yeo’s talk at New Scientist Live 2026.
Over 1 billion people worldwide live with obesity, having excessive body fat that presents a health risk.
Obesity is now thought to be a consequence of those with genetic susceptibility being exposed to an obesogenic environment, one which promotes excessive energy intake and decreased energy expenditure.
40-70% of variation in body weight within the population can be explained by genetic factors, rather than environmental factors, challenging the mainstream view that obesity is caused mainly by a poor lifestyle.
How do weight loss drugs work?
GLP-1 mimetic drugs such as Ozempic and Wegovy are commonly used to treat type 2 diabetes and also obesity, with 1 in 8 Americans being on these medications. GLP-1 is a hormone naturally found in the body, released in the gut when food is consumed.
It has numerous functions, one being appetite reduction.
Ozempic contains semaglutide which has a similar structure to human GLP-1, but is much longer acting and is not degraded as quickly. As a consequence, appetite suppression is sustained, leading to weight loss.
Do they actually cure obesity?
It can be argued that these drugs do not tackle the root causes of obesity and once the medication is terminated, patients often put the weight back on.
This effect can be likened to that of many other long term medications such as high blood pressure medication, meaning that weight loss medications may need to be considered as life-long treatments to be effective in the long term.
The effects of coming off these medications may be offset by trying to implement behaviour changes whilst undergoing treatment.
It must be noted that there is a link between socioeconomic status and obesity rates, with the prevalence of obesity being nearly twice as high in the poorest in our society. This disparity may reflect inadequate access to nutritious foods and opportunities to exercise, highlighting the importance of addressing poverty and healthcare inequalities in managing obesity.
How are they used in the UK?
GLP-1 mimetic injections are not yet routinely available on the NHS for weight loss, so 95% of people in the UK taking them are doing so privately.
However, in 2031 Ozempic comes off patent in the UK, making it significantly less expensive so much more accessible to the wider population. This raises concerns about inappropriate use and risks to those using it as a cosmetic tool to lose weight without a medical indication.
Ultimately, weight loss injections do represent an advancement in the treatment of obesity as a disease for those who need it. However, they do not address the deeper socioeconomic and environmental causes of obesity.
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