Without urgent policy reform and action, over half the world’s adult population (3.8 billion) and a third of all children and adolescents (746 million) are forecast to be living with overweight or obesity by 2050—posing an unparalleled threat of premature disease and death at local, national, and global levels, according to a major new analysis from the Global Burden of Disease Study BMI Collaborators, published in The Lancet.
Massive global failures in the response to the growing obesity crisis over the past three decades contributed to a startling increase in the number of adults (aged 25 and older) and children and adolescents (aged 5-24 years) with overweight and obesity worldwide, rising from 731 million and 198 million respectively in 1990, to 2.11 billion and 493 million in 2021.
“The unprecedented global epidemic of overweight and obesity is a profound tragedy and a monumental societal failure.”
The study predicts a substantial (121%) rise in obesity among young people globally, with the total number of children and adolescents with obesity predicted to reach 360 million by 2050 (an additional 186 million from 2021).
The substantial increases in obesity forecast between 2022 and 2030, underscore the urgent need for action.
“The unprecedented global epidemic of overweight and obesity is a profound tragedy and a monumental societal failure,” said lead author Professor Emmanuela Gakidou from the Institute for Health Metrics and Evaluation (IHME), University of Washington, USA. “Governments and the public health community can use our country-specific estimates on the stage, timing, and speed of current and forecasted transitions in weight to identify priority populations experiencing the greatest burdens of obesity who require immediate intervention and treatment, and those that remain predominantly overweight and should be primarily targeted with prevention strategies.”
The new analysis estimated the prevalence of overweight and obesity for children and young adolescents (aged 5-14 years), older adolescents (aged 15-24 years), and adults (aged 25 and older) in 204 countries and territories from 1990 to 2021 with forecasts from 2022 to 2050 (assuming continuation of past trends and patterns as well as policies and interventions) using up to 1,350 unique data sources, including all major multi-country and national survey data.
Adjustments were made to correct for self-reporting bias.
The study used body mass index (BMI) for adults—widely used to track current global trends. For individuals older than 18 years, overweight was defined as having a BMI of 25 kg/m² to less than 30 kg/m² and obesity was defined as a BMI of 30 kg/m² or higher.
For individuals younger than 18 years definitions were based on International Obesity Task Force criteria.
60% of adults predicted to have overweight or obesity by 2050
Almost half of the global adult population (1 billion males and 1.11 billion females aged 25 or older) were estimated to be living with overweight or obesity in 2021.
The prevalence of obesity more than doubled worldwide between 1990 and 2021 in both adult men (from 5.8% to 14.8%) and women (10.2% to 20.8%).
Especially high levels have already been reached in Oceania and north Africa and the Middle East, with over 62% of adult males in Nauru, Cook Islands, and American Samoa, and over 71% of adult females in Tonga and Nauru living with obesity in 2021.
Among high-income countries, the USA had the highest rates of obesity, with around 42% of males and 46% of females affected by obesity in 2021.
Continuation of these trends would see global rates of overweight and obesity among adults rise from an estimated 43.4% in 2021 to around 57.4% for men in 2050, and from 46.7% to 60.3% for women, with the largest increases projected in Asia and sub-Saharan Africa, driven by growing populations.
This would mean an estimated 1.69 billion additional adults living with overweight or obesity by 2050 (raising the total to 3.8 billion, of whom 1.95 billion will have obesity).
While the largest number of adults with overweight and obesity are still expected in China (627 million), India (450 million) and the USA (214 million) in 2050, the number in sub-Saharan Africa is forecast to rise by over 250% to 522 million, driven by population growth.
Worldwide, Nigeria stands out for its predicted rise in adults with overweight and obesity, with the number projected to more than triple from 36.6 million in 2021 to 141 million in 2050—making it the country with the fourth-largest population of adults with overweight and obesity.
Around one in three adults worldwide are expected to be affected by obesity in 2050—of whom around a quarter are forecast to be 65 years and older—with the highest levels in the United Arab Emirates and Nauru (more than 80% of males expected to have obesity in 2050); and in Tonga and Egypt.
“Obesity rates are skyrocketing across sub-Saharan Africa, with 522 million adults and more than 200 million young people expected to be living with overweight or obesity by 2050,” said co-author Awoke Temesgen, clinical Associate Professor at IHME. “This has added a double burden to the already overstretched healthcare systems that are ill-equipped to handle the extraordinary rise in obesity-related disease. Action is urgently needed to implement preventative initiatives such as polices on marketing of unhealthy foods and planning to include facilities for exercise and playing fields in schools.”
Importantly, the authors note that more recent generations are gaining weight faster than previous ones and obesity is occurring earlier, increasing the risk of complications such as type 2 diabetes, high blood pressure, cardiovascular diseases, and multiple cancers occurring at younger ages. For example, in high-income countries, approximately 7% of men born in the 1960s were living with obesity at the age of 25, but this increased to around 16% for men born in the 1990s, and is forecast to reach 25% for men born in 2015.
One in three young people predicted to have overweight or obesity in 2050
The new analysis estimates that the global prevalence of overweight and obesity in young people rose substantially between 1990 and 2021, doubling in both children and younger adolescents (from 8.8% to 18.1%) and older adolescents (from 9.9% to 20.3%), affecting 493 million young people in 2021. Similarly, obesity rates in children and adolescents tripled from 2% to nearly 7%, with 174 million young people living with obesity in 2021.
“But if we act now, preventing a complete transition to global obesity for children and adolescents is still possible.”
The study predicts that overweight during childhood and adolescence will stabilise between 2021 and 2050 as larger numbers in all world regions shift to obesity, with substantial increases expected immediately between 2022 and 2030, with increases continuing beyond 2031 to 2050.
Globally, more 5–14-year-old males are forecast to be living with obesity compared to overweight by 2050 (16.5% vs 12.9%), whereas in females (5-24 years) and older males (15-24 years), overweight is still expected to remain more prevalent than obesity.
The most rapid accelerations in obesity are forecast in north Africa and the Middle East and Latin America and the Caribbean, where one-third of all the world’s children and adolescents with obesity (130 million) are expected to live in 2050.
The transition to obesity predominance (versus overweight) is also expected to be overwhelming for several Oceanic countries (e.g., Cook Islands, Nauru, Tonga) where levels of obesity are expected to reach 60-70% by 2050, as well as for heavily populated countries such as Nigeria (18.1 million), India (26.4 million), Brazil (17.8 million), China (35.2 million), and the USA (22.1 million) where the numbers of young people with obesity are forecast to soar.
“But if we act now, preventing a complete transition to global obesity for children and adolescents is still possible,” said co-lead author Dr Jessica Kerr from Murdoch Children’s Research Institute in Australia. “Our estimates identify children and adolescents in much of Europe and south Asia living with overweight who should be targeted with obesity prevention strategies. We have also identified large populations, particularly adolescent girls, in North America, Australasia, Oceania, north Africa and the Middle East, and Latin America that are expected to tip over to obesity predominance and require urgent, multifaceted intervention and treatment. This is essential to avoid intergenerational transmission of obesity and to prevent a wave of serious health conditions and dire financial and societal costs for future generations.”
A new roadmap for obesity prevention
The authors stress that 5-year action plans (2025-2030) are urgently required to curb the rise in obesity and help inform new goals and targets for the post-2030 Sustainable Development Goal-era. The authors call for more concerted efforts to deliver comprehensive, transdisciplinary interventions tailored to each county’s unique socio-demographic, economic, environmental, and commercial situation.
“Preventing obesity must be at the forefront of policies in low- and middle-income countries,” said Dr Kerr. “Policy action in these regions must balance the challenges of overnutrition with undernutrition and stunting, with interventions ranging from support for nutritional diets and regulating ultra-processed foods to promoting maternal and child health programmes that encourage pregnant women to follow a healthy diet and breastfeed. This is no time for business as usual. Many countries only have a short window of opportunity to stop much greater numbers shifting from overweight to obesity.”
She added, “Ultimately, as global obesity rates continue to soar, much stronger political commitment is needed to transform diets within sustainable global food systems and to support comprehensive strategies that improve people’s nutrition, physical activity and living environments, whether it’s too much processed food or not enough parks.”
The authors note some important limitations, including that while the study uses the best available data, predictions are constrained by the quantity and quality of past data as well as systemic biases from self-reported data, which are likely to remain despite attempts to correct for bias.
They also note that the definition of overweight and obesity is based on BMI, which does not account for variations in body structure across ethnic groups and subpopulations.
Finally, the study did not consider the potential impact of interventions, such as the scale-up of GLP-1 anti-obesity medications, that could alter the longer-term forecasting trends of overweight and obesity.
Writing in a linked Comment, Thorkild I A Sørensen of the University of Copenhagen, Denmark (who was not involved with the study) said: “The scale of the epidemic is such that solutions will have to be public health interventions, also considering the profound macro-level and micro-level heterogeneity of the development of the epidemic. In particular, the consistent and unexplained tendency towards a higher prevalence among socially deprived groups enhances the challenges. The most pressing question concerns which interventions will be both feasible and effective. Although the components of the global environment, presumed to be driving the epidemic, in principle should be reversible, rolling them back to before the emergence or acceleration of the obesity epidemic is clearly unrealistic…Further understanding of the causes and mechanisms of obesity development could pave the way to improved lasting prevention.”
