Obesity among children is rising fastest in low- and middle-income countries, study finds

Childhood and adolescent obesity is no longer increasing at the same pace across the world, according to a new study published in the journal Nature on May 13, 2026.

While obesity rates among young people have slowed, stabilised or even slightly declined in many high-income countries, they continue to rise steadily — and in some cases rapidly — across large parts of Asia, Africa, Latin America and the Pacific Islands.

The study analysed obesity trends from 1980 to 2024 using data from 4,050 population-based studies covering 232 million participants aged five years and older across 200 countries and territories.

Researchers examined obesity patterns through a measure called velocity, which reflects the annual change in obesity prevalence in percentage points per year.

The study found that obesity has become far more common globally than it was in the late 20th Century. Since the 1990s, the rapid increase in obesity has often been described as an epidemic.

However, previous reports mostly compared obesity prevalence across decades and did not closely assess how obesity trends evolved over shorter periods within individual countries.

To better understand these patterns, the scientists calculated annual obesity growth rates among children, adolescents and adults separately.

Adult obesity was defined as a body mass index, or BMI, of 30 kilogrammes per square metre or higher or higher, while for children and adolescents it was defined using World Health Organization growth standards.

High-income countries slow down

The findings showed that obesity prevalence among school-aged children and adolescents increased in nearly every country studied between 1980 and 2024.

The rise ranged from 0.6 to 27 percentage points among girls and from 0.4 to 35 percentage points among boys. However, the pace of increase varied significantly across regions.

In most high-income countries in Western Europe, North America and Australasia, as well as Japan and Taiwan, obesity growth among children largely occurred before 2000.

Since then, rates have slowed substantially, stabilised or, in some cases, slightly declined.

Countries such as Denmark, France, Switzerland and the Netherlands recorded very low or near-zero annual increases over the past decade.

In some countries, including France, Italy and Portugal, obesity growth may even have turned slightly negative.

Fastest growth in poorer regions

In contrast, obesity among children and adolescents continued to rise steadily or accelerate in many low- and middle-income countries.

Researchers found that by 2024, obesity growth rates were at their highest levels since 1980 in 110 of 200 countries for girls and in 91 countries for boys, most of them in developing regions.

Rapid increases were recorded even in countries where obesity prevalence remains relatively low, including Tanzania, Rwanda, Ethiopia, Nepal and Bangladesh.

At the same time, obesity had already risen to high levels in some Caribbean and Pacific Island nations, including Niue and the Bahamas; some countries in the Middle East and North Africa, including Saudi Arabia, Qatar and Oman; Southeast Asian countries such as Brunei and Malaysia; and parts of Latin America, including Chile.

These highly varied dynamics suggest that the social, economic and technological trends influencing the availability, affordability and consumption of different foods may have helped slow the rise in obesity in high-income countries, but still require stronger policy intervention in low- and middle-income countries.

The study suggests that rapid urbanisation, changing diets, increased consumption of ultra-processed foods and lower physical activity are contributing to the surge in developing regions.

Scientists cautioned that obesity is associated with serious health risks, including cardiovascular disease, kidney, liver and respiratory diseases, diabetes and some cancers.