More than one billion people now living with obesity, global analysis suggests

New analysis led by Imperial’s School of Public Health shows obesity rates have increased dramatically over the last three decades.

One in eight people in the world is now living with obesity, according to a new analysis which highlights changes to global trends in malnutrition over more than 30 years.

The work, published in The Lancet, finds that the total number of children, adolescents and adults worldwide living with obesity has surpassed one billion.

The report highlights that these trends, together with the declining prevalence of people who are underweight since 1990, make obesity the most common form of malnutrition in most countries.

Researchers estimate that among the world’s children and adolescents, the rate of obesity in 2022 was four times the rate in 1990. While among adults, the obesity rate more than doubled in women and nearly tripled in men.

In total, an estimated159 million children and adolescents and 879 million adults were living with obesity in 2022. 

The work follows on from previous estimates of global burden of obesity and underweight, carried out by the same group in 2017.

According to the researchers, the latest findings highlight an urgent need for comprehensive policies to tackle the burden of malnutrition, including improving the accessibility and affordability of nutritious food, as well as prevention and management strategies for obesity and underweight.

Professor Majid Ezzati, of Imperial’s School of Public Health, and senior author of the study, said: “It is very concerning that the epidemic of obesity that was evident among adults in much of the world in 1990 is now mirrored in school-aged children and adolescents.

“At the same time, hundreds of millions are still affected by undernutrition, particularly in some of the poorest parts of the world. To successfully tackle both forms of malnutrition it is vital we significantly improve the availability and affordability of healthy, nutritious foods.” 

Global analysis

In the latest study, conducted by the NCD Risk Factor Collaboration (NCD-RisC) in collaboration with the World Health Organization (WHO), researchers set out to analyse trends in obesity and underweight – both forms of malnutrition which are detrimental to health in many ways.

Researchers analysed weight and height measurements from over 220 million people aged five years or older (63 million people aged five to 19 years, and 158 million aged 20 years or older), representing more than 190 countries.

More than 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. 

Rates of obesity

They found that between 1990 and 2022, the proportion of the world’s children and adolescents who were affected by underweight fell by around one fifth in girls and more than one third in boys. The proportion of the world’s adults who were affected by underweight more than halved over the same period. 

It is very concerning that the epidemic of obesity that was evident among adults in much of the world in 1990 is now mirrored in school-aged children and adolescents Professor Majid Ezzati School of Public Health

Adults were classed as being affected by obesity if they had a BMI greater than or equal to 30kg/m2 and classed as underweight if their BMI was below 18.5kg/m2.

Among school-aged children (aged five to nine years) and adolescents (aged 10-19 years), the BMI used to define obesity and underweight depended on age and sex because there is significant increase in height and weight during childhood and adolescence.

From 1990 to 2022, global obesity rates more than quadrupled in girls (1.7% to 6.9%) and boys (2.1% to 9.3%), with increases seen in almost all countries. The proportion of girls who were underweight fell from 10.3% in 1990 to 8.2% in 2022, and for boys it fell from 16.7% to 10.8%. Among girls, a decrease in the rates of underweight was detected in 44 countries, whilst among boys, a decrease was noted in 80 countries.

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 (8.8% to 18.5%) and nearly tripled in men (4.8% to 14.0%) between 1990 and 2022. The proportion of adults who were underweight halved between 1990 and 2022 (14.5% to 7.0% in women; 13.7% to 6.2% in men). 

Changing trends

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).

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 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). 

Dr Tedros Adhanom Ghebreyesus, WHO Director-General, said: “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.

“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.”

Double burden

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.

Dr Guha Pradeepa, study co-author from the Madras Diabetes Research Foundation, warns that major global issues risk worsening both forms of malnutrition, saying: “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.

“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.” 

The rise in double burden has been greatest in some low-income and middle-income countries, particularly those in Polynesia and Micronesia, the Caribbean, and the Middle East and North Africa. These countries now have higher obesity rates than many high-income industrialised countries, especially those in Europe. 

This study was funded by UK Medical Research Council, UK Research and Innovation, and the European Commission.

The full ranking and breakdown of countries for adults and for school-aged children and adolescents is available on the NCD-Risc website.

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‘Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population representative studies with 222 million children, adolescents, and adults’ by NCD Risk Factor Collaboration (NCD-RisC) is published in The Lancet. DOI: https://doi.org/10.1016/S0140-6736(23)02750-2

The study was conducted by researchers from the NCD Risk Factor Collaboration (NCD-RisC), a worldwide network of over 1,500 researchers and practitioners that provides rigorous and timely information on NCD risk factors for all countries. NCD-RisC is coordinated by the WHO Collaborating Centre on NCD Surveillance, Epidemiology and Modelling at Imperial College London, and collaborates with the World Health Organization (WHO) on the work.  

See the press release of this article