Nearly 60% of all adults and a third of all children in the world will be overweight or fat by 2050, unless governments intervene, a big new study said Tuesday.

The research published in the Lancet Medical Journal used data from 204 countries to paint a bleak picture of what it described as one of the major health challenges of the century.

“The unprecedented global epidemic of overweight and obesity is an in-depth tragedy and a monumental societal failure,” said lead author Emmanuela Gakidou of the US-based Institute for Health Metrics and Evaluation (IHME) in a statement.

The number of obese or obese people around the world rose from 929 million in 1990 to 2.6 billion in 2021, the study found.

Without a serious change, researchers estimate that 3.8 billion adults will be overweight or fat of 15 years – or about 60% of the global adult population by 2050.

The world’s health systems will come under paralyzing pressure, the researchers warned, with about a quarter of the world’s overweight expected to be over 65 at the time.

They also predicted an increase of 121% in obesity among children and adolescents around the world.

One third of all overweight young people will live in two regions – North Africa and the Middle East and Latin America and the Caribbean – in 2050 the researchers warned.

But it’s not too late to act, said student author Jessica Kerr from Murdoch Children’s Research Institute in Australia.

“Much stronger political commitment is needed to transform diets in sustainable global food systems,” she said.

This obligation was also necessary for strategies, “that improves people’s nutrition, physical activity and living environments, whether too much processed food or not enough parks,” Kerr said.

More than half of the world’s overweight or obese adults already live in only eight countries – China, India, USA, Brazil, Russia, Mexico, Indonesia and Egypt, the study says.

While bad diet and sedentary lifestyle are obviously drivers of the obesity epidemic, “there is still questionable” about the underlying causes of this, Thorkild Sorensen said, a researcher at Copenhagen University, who is not involved in the study.

For example, socially deprived groups have a “consistent and inexplicable trend” towards obesity, he said in a coherent comment in the lancet.

The research is based on figures from the global burden of disease study from IHME, which brings together thousands of researchers around the world and is funded by Bill and Melinda Gates Foundation.