Are weight loss jabs the solution to the obesity crisis?

Paul Fletcher, Bernard Wolfe Professor of Health Neuroscience in the University of Cambridge’s Department of Psychiatry

There is unlikely to be a single solution to the obesity crisis. Sensible practice, at the clinical and social levels, will integrate a range of approaches helping people to achieve and maintain weight loss. In this respect, Ozempic and drugs like it may prove extremely valuable, particularly in a field where drug treatments have proven limited in their effectiveness or unacceptable in their side effects.

There are a range of factors contributing to obesity. Undoubtedly, in recent decades, the wide and ready availability of aggressively-marketed, highly palatable, energy-dense foods is key.

There is a high degree of variability in who is vulnerable and who is resistant to the effects of this ‘obesogenic environment’ and this variability is, in large part, genetically determined.

Unfortunately, there are prevailing simplistic and moralistic notions that this vulnerability to obesity lies in some sort of failure of will-power or self-control.

In fact, research - much of it at the Institute for Metabolic Science in Cambridge - has shown that it relates to the neural circuitry that controls appetite, satiety and the extent to which food stimuli can capture and drive behaviours. Such people may be swimming against a very strong tide, and it is rarely helpful simply to tell them to swim harder.

If we are prepared to put aside the misplaced moral judgments, we can see drugs like Ozempic as one valuable part of the attempt to redress a balance, giving vulnerable people a greater protection against the effects of an environment that may be markedly more challenging than it is in people whose genetic make-up doesn’t confer this vulnerability.

As such, we should welcome these drugs as a part of the solution, while at the same time recognising that there is much work to be done in changing the unhealthy food environment.

Professor Theresa Marteau, Director of the University of Cambridge’s Behaviour and Health Research Unit

Given over half the world’s population is expected to be overweight or living with obesity by 2035, the obesity crisis requires many solutions.

Semaglutide treats obesity - it doesn’t prevent it. As a treatment it is remarkably effective, generating average weight losses after 68 weeks of around 12kgs. But the cost is huge. In England alone it could double the annual NHS prescription budget of £17bn, with a high rate of weight gain when the drug is stopped. And, like pre-existing treatments including bariatric surgery, it has serious side effects. Not everyone will want it.

Tackling the obesity crisis requires us to fix the broken food system that ruins not only our health but also the planetary systems on which all life depends.

My research focuses on one part of this broken system: the cues or prompts in our everyday environments that, often without our awareness, lead us to consume more energy than we need - mainly from foods high in fat, sugar and salt. Interventions that can change these environments can be grouped into those that target the Affordability, Advertising and Availability of less and more healthy foods. We need interventions targeting each of these.

I will illustrate the potential for Availability interventions to contribute. Companies pay stores to display their products in prominent places and in 2013 we attempted to estimate the size of this effect. Focusing just on drinks, we analysed a dataset that linked sales of products with where in store they were placed.

The effects we observed were surprisingly large. Sales of alcohol displayed on end-of-aisles were between 23% and 46% higher, and for non-alcoholic drinks, between 52% and 114% higher.

Restricting the use of aisle ends for alcohol and other less healthy products emerged as a promising option to reduce their sales, and in turn, consumption.

Although based on an observational study, our findings were deemed robust enough to inform policies to reduce consumption of unhealthy food and alcohol in the UK, Australia, USA and UNICEF. Further studies replicated our initial findings.

The UK government’s 2020 obesity strategy included regulation to restrict where in stores foods high in fat sugar and salt could be displayed. In preparation, an economic impact assessment was conducted. This estimated improved health benefits of £67 billion over 25 years from prohibiting placement of such foods on aisle ends and other prominent positions, with a cost to businesses of £5.5 billion mainly from lost sales. This prohibition came into force on 1 October 2022.

This is just one of several interventions that, if implemented as a package, could redesign our everyday environments and reverse the shocking trends in overweight and obesity. And, for those still needing Ozempic and drugs like it, redesigned environments would help maintain their weight-loss post-treatment.