Popular weight loss drugs like Wegovy and Ozempic are not a 'silver bullet' for addressing the world's obesity epidemic, the World Health Organization (WHO) warns.

Dr Francesco Branca, WHO director of nutrition and food safety, drugs for obesity are helpful but must form part of a holistic approach to weight loss. Drugs for obesity are important but must be 'part of a comprehensive approach,' Mr Branca said. 'This is not a silver bullet.' 

He said that other interventions, including diet and exercise, remain critical to help manage obesity.

Talking to foreign media, he said the global health body is first revising guidelines for treating children and adolescents with obesity, and will then update recommendations for adults.  

The latest WHO data shows that the percentage of children and adolescents aged five to 19 who are obese or overweight has risen to just over 18 percent in 2016 from four percent in 1975, and this now represents more than 340 million people. 

Some have declared obesity a global epidemic, as more than half the world's population will be overweight or obese by 2035.

The WHO last issued global guidelines on the topic in 2000, which are used as a blueprint for countries without the resources to draft their own plans.

Wegovy and Mounjaro were originally developed for type 2 diabetes to help control blood glucose. More recently, they have been shown to help people lose around 15% of their body weight, capturing the attention of patients, investors, and even celebrities. 

Part of a class of drugs known as GLP-1 agonists, they are given by a weekly injection and work by affecting hunger signals to the brain and slowing the rate at which a person’s stomach empties, making them feel full longer.

Studies suggest people are likely to have to take drugs for the rest of their lives to keep the weight off.

Wegovy is approved for weight loss in the United States and Europe, while Mounjaro is expected to receive U.S. approval later this year. The enormous demand for the drugs is expected to be worth $100 billion in annual sales within a decade, with as many as 10 different drugs on the market.

U.S. medical groups are also reviewing their obesity treatment guidelines to consider the best use of Wegovy and similar drugs, with some specialists advocating broad use while others recommend prioritizing them for high-risk patients with health conditions, like diabetes or heart disease, that are exacerbated by excess weight.

The American Academy of Pediatrics has recommended using such medicines in children aged 12 or older with obesity, even though the long-term impacts have yet to be studied.