Half the World Could Be Obese by 2035: Here's what to know

A startling report from the World Obesity Federation warns that by 2035, more than half of the global population will be overweight or obese. But a groundbreaking genetic discovery from the University of Copenhagen may provide a powerful tool for early prevention.

An international team of researchers has developed a revolutionary test known as the Polygenic Risk Score (PGS), which can predict a child's likelihood of developing obesity later in life before the age of five. This cutting-edge predictive tool offers an unprecedented opportunity for early and effective intervention in the global fight against obesity.

The PGS functions as an advanced algorithm that evaluates the combined impact of thousands of genetic variants known to influence obesity risk, particularly those affecting brain mechanisms related to appetite. Its strength lies in its unprecedented scale: it is based on genetic data from over five million individuals, making it the most comprehensive and diverse dataset ever used for obesity prediction.

Researchers say the new test is twice as accurate in predicting obesity risk as previous methods.

This development comes at a critical juncture for global public health. Obesity rates have soared in recent decades. In 2003, approximately 10.5% of adults worldwide were classified as obese. By 2022, that number had risen to 18.7%, an increase of 78% over two decades.

While current strategies like lifestyle changes, surgery, and medication remain out of reach or ineffective for many, early detection of genetic risk in young children could pave the way for targeted interventions. These could include promoting healthy eating habits and physical activity early in life, potentially preventing obesity before it begins.

“This brings us closer to clinically useful genetic screening,” said Professor Ruth Loos, one of the lead researchers on the project.

Importantly, the study emphasizes that genetics is not destiny. Though the PGS can identify individuals with elevated genetic risk, the research shows these individuals can still respond positively to weight-loss interventions. However, they may also be more prone to weight regain after treatments end.

Published in the journal Nature Medicine, the study was the result of a global collaboration involving more than 600 scientists from over 500 institutions. Despite its success, the PGS currently performs significantly better in predicting obesity among individuals of European descent than those of African descent, a limitation that highlights the need for broader representation and further research.

As obesity rates continue to climb, tools like the PGS may play a vital role in shifting the focus from treatment to prevention, potentially changing the global health trajectory for future generations.

Credit: World Obesity Atlas 2025