Obesity Wonder drugs altering views of how our bodies and brains work

Obesity was once medicine's Cinderella subject, with some questioning whether the condition should even be viewed as a biological disorder. But the arrival of a new class of appetite-suppressing drugs that includes Ozempic and Wegovy has transformed obesity treatment into the most scientifically exciting and commercially lucrative area of healthcare.

- Hannah Devlin and Nicola Davis

These drugs lead to dramatic weight loss, are shifting perceptions of obesity and, according to a series of results announced at this week's European Congress on Obesity in Malaga, promise health benefits that extend far beyond weight management.

"It's been an extraordinary week," said Prof Susan Jebb, a public health nutrition scientist at the University of Oxford who has been researching obesity treatments since the 1980s and who presented landmark findings at the Malaga meeting. "Obesity has been in the background for so long and it's been such a slog," she added. "These drugs have energised the field and it has happened so fast."

First developed to help lower blood sugar levels as a diabetes treatment, it was quickly apparent that Novo Nordisk's drug semaglutide (the active ingredient in Ozempic and Wegovy jabs) had a dramatic effect on weight. The drug works by mimicking a natural hormone, GLP-1, released in the gut when we eat and which acts on receptors around the body, including the brain.

Eli Lilly's rival product, Mounjaro, contains the active ingredient tirzepatide. This emulates GLP-1 as well as a second hormone producing even more impressive results, according to the first head-to-head trial reported this week in which participants lost an average of 20% of their body weight after 72 weeks of treatment.

The benefits of being at a healthy weight are substantial, with one study published in January suggesting the jabs could reduce the risk of 42 diseases including heart disease, cancer, clotting disorders, Alzheimer's, chronic kidney disease, addiction and a range of psychiatric conditions. There is early evidence that these benefits go beyond what might be expected due to the drugs' metabolic effects.

"We absolutely know almost every aspect of health is better if you're a healthy weight," said Jebb. "What we haven't really nailed is whether those effects are independent of weight. My reading is, the jury is out."