Public health perspective on new weight loss medications

Most countries have seen substantial rises in the prevalence of obesity in recent decades. Effective, acceptable treatments are much needed, and the glucagon-like peptide (GLP-1) agonists semaglutide and tirzepatide, which work by suppressing appetite, may initially seem to fulfil that need.12 In one key trial, semaglutide plus a “lifestyle” intervention for adults (74% women) with obesity (mean body mass index (BMI) 37.9) led to a 12.7 kg (95% confidence interval 11.7 to 13.7) greater weight loss than the lifestyle intervention alone (15.3 kg v 2.6 kg). This weight loss is substantially more than that associated with other pharmaceutical and behavioural options.234

Reliable usage data are lacking, but these drugs seem increasingly popular despite a lack of long term data on safety. Serious reported adverse effects include pancreatitis, bowel obstruction, gastroparesis, pulmonary aspiration during anaesthesia, suicidal ideation, and self-harm; these warrant further investigation.5 For many people with obesity and a high risk of comorbidities, the benefits are likely to outweigh risks, at least in the short term. But will the new weight loss medications work from a public health perspective?

Firstly, relatively …