Study reveals obesity to impact over half of adults and third of children by 2050

According to a major new analysis from the Global Burden of Disease Study BMI Collaborators, published in The Lancet, without urgent policy reform and action, around 60% of adults (3.8 billion) and a third (31%) of all children and adolescents (746 million) are forecast to be living with either overweight or obesity by 2050 - posing an unparalleled threat of premature disease and death at local, national, and global levels.

Most comprehensive global analysis to date estimates that overweight and obesity rates in adults (aged 25 or older) and children and adolescents (aged 5-24 years) more than doubled over the past three decades (1990-2021), affecting 2.11 billion adults and 493 million young people worldwide in 2021.

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.

Weight gain varies widely across the globe with more than half of the world's adults with overweight or obesity in 2021 living in just eight countries - China (402 million), India (180 million), the USA (172 million), Brazil (88 million), Russia (71 million), Mexico (58 million), Indonesia (52 million), and Egypt (41 million).

Globally, the predicted surge in child and adolescent obesity is expected to outpace the increase in overweight, with substantial increases expected immediately (2022-2030). Children and young adolescents, especially males, are expected to fare worse - with levels of obesity (16.5%) overtaking overweight (12.9%) in males aged 5-14 years by 2050.

By 2050, one in three young people with obesity (130 million) are forecast to be living in just two regions - north Africa and the Middle East and Latin America and the Caribbean - with deleterious health, economic, and societal consequences.

Additionally, nearly a quarter of the world's adult population with obesity in 2050 are predicted to be aged 65 or older, intensifying the strain on already overburdened health-care systems and wreaking havoc on health services in low-resource countries.

The authors say the findings underscore the imperative for immediate action to prevent an unprecedented global epidemic of overweight and obesity.

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.

Lead author Professor Emmanuela Gakidou from the Institute for Health Metrics and Evaluation (IHME), University of Washington, USA notes "the unprecedented global epidemic of overweight and obesity is a profound tragedy and a monumental societal failure.

"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."

Co-lead author Dr Jessica Kerr from Murdoch Children's Research Institute in Australia added "but if we act now, preventing a complete transition to global obesity for children and adolescents is still possible.

"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.

"Preventing obesity must be at the forefront of policies in low- and middle-income countries. 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.

"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."

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.

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.

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.

Access full study in The Lancet