Obesity rates found to be levelling off and declining in many nations

Image credit: World Obesity Federation

A new analysis of global obesity trends since the 1980s challenges the idea of a ‘global epidemic’ of obesity.

The research reveals rising levels of obesity have slowed, stabilised and possibly even reversed in many nations.

The global report was put together by a collaboration of researchers, including from Southampton. It has now been published in the journal Nature.

A more optimistic picture

The analysis was led by researchers from Imperial College London, via the NCD Risk Factor Collaboration (NCD-RisC).

The research looked at more than four decades of health data from 200 countries and territories, covering the period from 1980 to 2024.

The findings come as experts from around the world meet at the European Congress on Obesity (ECO 2026) in Istanbul this month. They provide a more optimistic picture of progress than previously reported.

The research shows that the increase in obesity rates has slowed or levelled off in most high-income countries. This is despite rapid rises at the end of the 20th Century.

In some high-income countries rates may have even begun to decline. This includes France, Italy and Portugal.

The researchers say these results suggest previous claims of a ‘global epidemic’ of obesity are likely to be an oversimplification.

They say these claims mask the huge diversity seen across countries. This can be driven by a range of factors, especially the availability and affordability of healthy food.

However, obesity prevalence continues to rise in many low‑ and middle‑income countries. This includes Africa, Asia, Latin America, and Pacific and Caribbean island nations.

The researchers suggest we should focus on the pace of change in obesity over time, rather than just the prevalence. By doing so, they say we can learn where urgent action is needed.

This includes robust health and food policies to help nations adapt and manage public health during economic, technological and nutritional transitions.

Professor Majid Ezzati, from the School of Public Health at Imperial College London, led the analysis.

He said: “We now need to find out why some countries are doing so much better than others, and apply the lessons to stop obesity from increasing.

“Ultimately, this analysis shows that the trend towards obesity is not inevitable, and that it is possible for policy makers to intervene to stop and even reverse growing obesity.”

Children improving first

Obesity rates in high-income countries slowed first in school-aged children and adolescents. Adults followed the same pattern about a decade later.

In most high-income western countries, the rise in obesity among children occurred before the millennium. This trend slowed, plateaued and even reversed slightly after the year 2000.

Denmark experienced the earliest documented slowdown, around 1990. This was followed by other European countries during the 1990s. These included Iceland, Switzerland, Belgium and Germany.

By the mid-2000s, growing obesity rates among school-aged children and adolescents in most high-income countries started to stabilise. In some, they even started to decline.

The exceptions were among children in Australia, Finland and Sweden. There, obesity increased steadily or accelerated.

However, the levelling off has happened at very different national prevalences across countries.

In many western European countries and Japan, obesity growth plateaued or reversed when prevalence was below 10% of the school-age population. This meant fewer than one in ten children had obesity.

By comparison, in the USA and New Zealand, obesity stabilised when levels were much higher, at 19-23% of the school-age population. This meant as many as one in four school children had obesity. The same trend was seen in adults.

In the UK, the research showed the rise in obesity has slowed or plateaued for both children and adults. However, this has happened at moderately high prevalence.

10-12% of children and 27-30% of adults had obesity in 2024. The UK remains mostly in the top 10 countries among high-income western countries for obesity rates.

Professor Keith Godfrey from the NIHR Southampton Biomedical Research Centre and the University of Southampton contributed to the research.

He said: “In England, the most recent National Child Measurement Programme data show that 10.5% of school children in reception and 22.2% of year 6 children were living with obesity.

“Excluding the 2020 to 2021 peak during the COVID pandemic, this is the highest obesity prevalence seen in reception since the measurement programme began in 2006.

“At national, regional and local levels, there are large and widening variations in obesity prevalence in young children, associated with persistent inequalities by ethnic group and deprivation.

“The findings are encouraging in showing that obesity rates have stabilised or even started to decline in several European countries.

“They give hope that concerted action to improve our national food system could likewise start to reduce the wide disparities in child obesity in the UK.”

Global obesity trends

Previous reports on the global state of obesity have typically compared prevalence of obesity over decades. This includes those conducted by NCD-RisC in collaboration with the World Health Organization (WHO).

This approach can provide valuable insights. However, it can make it difficult to track progress in controlling obesity. This is especially true for recent changes that reflect policy innovation.

In the latest analysis, researchers used velocity of obesity as a key measure. This is calculated as the annual absolute change in prevalence of obesity. It is reported in percentage-points-per-year. Using this method, they were able to provide a clearer picture of where increases in obesity are accelerating, stabilising, or reversing.

The team analysed weight and height measurements from over 232 million people. This included 70 million people aged five to 19 years, and 162 million aged 20 years or above. The analysis covered 200 countries and territories.

More than 1,900 researchers contributed to the study. It looked at body mass index (BMI) to understand how obesity rates have changed worldwide from 1980 to 2024.

Obesity was defined as a BMI of 30 kg/m2 or above for adults. It was defined as a BMI over two standard deviations above the median of the WHO growth reference for children and adolescents.

Estimates of obesity were adjusted for differences in how the population was distributed in different ages. This was done through a process called age standardisation.

Growing gap between countries

The analysis shows that obesity continues to rise, and is even accelerating, in most low- and middle-income countries. This divergence from high-income nations highlights growing global inequalities in nutrition and health.

The researchers recommend tailored public health policies to address the growing gap. These could include policies focused on the availability and affordability of healthy foods for countries and communities who cannot currently afford and access them.

Over the last decade, new obesity medications have become widely available. These include GLP-1 receptor agonists.

The researchers state that the introduction of these drugs does not yet explain the changes seen in their study. However, they say these are likely to play an important role in future trends, especially if access and affordability are improved.

Professor Ezzati explained: “At this stage it’s probably too early to say whether GLP-1 drugs have had a direct impact in entire populations, even though they are beneficial for patients who use them. The focus should be on making them more affordable to all who need them

around the world.”

The authors highlight a number of limitations to the study, including the amount of data available, which varied by region.

The research was funded by the UK Medical Research Council and UK Research and Innovation. It was supported by funding through the European Union.