The rapid rise of GLP-1 medications such as semaglutide—marketed as Ozempic and Wegovy—has transformed the global conversation around weight loss, introducing a new era in obesity treatment. These drugs, originally developed to regulate blood sugar, have shown significant promise in promoting weight loss, prompting renewed attention from health authorities and researchers alike.
Two recent developments have given the field fresh momentum: the World Health Organisation’s (WHO) publication of new guidance on GLP-1 and related medications, and emerging studies comparing these drugs with bariatric surgery. Together, they signal a major shift in how obesity—a condition affecting more than one billion people worldwide—is understood and treated.
Obesity significantly increases the risk of numerous health conditions, including heart disease, stroke, several cancers, type 2 diabetes, osteoarthritis, sleep apnoea and depression. Experts say that treatments capable of curbing rising global obesity rates could reshape public health outcomes for decades to come.
According to Dr Francesca Celletti, who led the development of the WHO guideline, the new recommendations mark a “groundbreaking” departure from the organisation’s traditional focus on lifestyle interventions such as diet and exercise. The updated guidance now formally endorses GLP-1 drugs as a treatment option for obesity. “GLP-1s are the first efficacious [medication] for obesity and for a population that has been neglected by society and by the health system,” Celletti told the *Journal of the American Medical Association*. “The fact that we have new science to address the neglected needs and to reboot the system is an amazing opportunity for the world that we shouldn’t miss.”
Despite this endorsement, the WHO has urged caution. The guideline stresses that behavioural interventions should accompany drug treatment and highlights key gaps in evidence. “First of all, we don’t know if this is a lifelong therapy,” Celletti said. “The long-term use and safety of the medicine are not actually known.”
She also pointed to known side effects, including nausea, vomiting and diarrhoea, as well as the potential for more serious risks such as acute pancreatitis. “If hundreds of millions of people are receiving this medicine in the next 10 years, even the most rare of adverse effects can become a considerable absolute number,” she said. “The current safety data is very inconclusive. We need many more studies.”
Alongside the caution, however, there is growing optimism. Researchers are finding that GLP-1 drugs may reduce a range of obesity-related complications, raising hopes that effective weight management could help reverse multiple metabolic diseases.
At the same time, bariatric surgery continues to play a significant role, particularly for patients with severe obesity. Studies suggest that surgery remains more effective for long-term weight loss: one found it produced roughly five times more weight loss than weekly injections of semaglutide or tirzepatide over two years. On average, bariatric patients lose 30 to 35 per cent of their total body weight in the first year, compared with 15 to 20 per cent for those on GLP-1 medications. The health benefits are also more immediate, with up to 60 per cent of patients with diabetes achieving remission after surgery.
Experts increasingly agree that surgery is best suited to those for whom lifestyle changes and medications are insufficient. Meanwhile, drug therapies may offer a less invasive alternative for a broader group of patients.
Perhaps the most far-reaching impact of the WHO guideline is its formal recognition of obesity as a complex, chronic and relapsing disease requiring lifelong care. This reframing places obesity in the same category as conditions such as hypertension and diabetes, which typically return when treatment stops.
Health advocates believe this shift could help reduce stigma and improve access to long-term care. By defining obesity as a chronic illness rather than a personal failing, the guidance may encourage health systems to treat it with the same seriousness and continuity as other major diseases—ushering in a new chapter in global public health policy.
