Over 1,500 researchers contributed to the study, which looked at body mass index (BMI) to understand how obesity and underweight have changed worldwide from 1990 to 2022.

From 1990 to 2022, global obesity rates more than quadrupled in girls and boys, with increases seen in almost all countries, the study found.

The proportion of underweight girls fell from 10.3 per cent in 1990 to 8.2 per cent in 2022, and for boys, it fell from 16.7 per cent to 10.8 per cent, the researchers said.

Among girls, a decrease in the rates of underweight was detected in 44 countries, whilst among boys, a decrease was noted in 80 countries, they said.

The total number of children and adolescents who were affected by obesity in 2022 was nearly 160 million (65 million girls and 94 million boys), compared to 31 million in 1990.

Whereas 77 million girls and 108 million boys were underweight in 2022, decreasing from 81 million for girls and 138 million for boys in 1990.

In adults, obesity rates more than doubled among women and nearly tripled in men between 1990 and 2022.

The proportion of adults who were underweight halved between 1990 and 2022.

In all age groups, the combined burden of both forms of malnutrition increased in most countries between 1990 and 2022, driven by increasing obesity rates.

However, the double burden of malnutrition declined in many countries in South and Southeast Asia, and in some countries in Africa for men, where the rate of underweight fell steeply.

The impact of issues such as climate change, disruptions caused by the COVID-19 pandemic, and the war in Ukraine risk worsening both rates of obesity and underweight, by increasing poverty and the cost of nutrient-rich foods,” said Guha Pradeepa, study co-author from the Madras Diabetes Research Foundation.

“The knock-on effects of this are insufficient food in some countries and households and shifts to less healthy foods in others.

To create a healthier world, we need comprehensive policies to address these challenges,” Pradeepa said.

In total, an estimated nearly 880 million adults were living with obesity in 2022 (504 million women and 374 million men), four and a half times the 195 million recorded in 1990 (128 million women and 67 million men), the researchers said.

Combined with the 159 million children living with obesity in 2022, this is a total of over one billion people affected by obesity in 2022.

Despite global population growth, 183 million women and 164 million men were affected by underweight in 2022, 45 million and 48 million fewer, respectively, than in 1990.

Overall, these trends have led to a transition where in most countries, a larger number of people are affected by obesity than being underweight.

In 2022, obesity rates were higher than rates of underweight for girls and boys in around two thirds of the world’s countries (133 countries for girls and 125 countries for boys).

“This new study highlights the importance of preventing and managing obesity from early life to adulthood, through diet, physical activity, and adequate care, as needed,” said WHO Director General Tedros Adhanom Ghebreyesus, .

“Getting back on track to meet the global targets for curbing obesity will take the work of governments and communities, supported by evidence-based policies from WHO and national public health agencies.

Importantly, it requires the cooperation of the private sector, which must be accountable for the health impacts of their products,” Ghebreyesus said in a statement.