Q&A: Global obesity and overweight projections to 2050

An independent population health research organization based at the University of Washington School of Medicine, the Institute for Health Metrics and Evaluation (IHME) works with collaborators around the world to develop timely, relevant, and scientifically valid evidence that illuminates the state of health everywhere. In making our research available and approachable, we aim to inform health policy and practice in pursuit of our vision: all people living long lives in full health.

This transcript has been lightly edited for clarity

How broad in scope is IHME's research into overweight and obesity globally, and what does it reveal?

Dr. Marie Ng

Along with the Murdoch Children’s Research Institute, we released two papers examining overweight and obesity among children, adolescents, and adults across 204 countries from 1990 to 2021, with extended forecasts to 2050. Overweight and obesity are major public health issues in many countries. Understanding the current situation and future trends are important for policy planning. Our research explores the number and proportion of people affected by overweight and obesity across different age groups and provides an outlook of what may occur in the next 30 years if no action is taken.

How many adults are currently overweight or obese, and what do you forecast the numbers to be by 2050?

Dr. Marie Ng

In 2021, we estimated that 2.1 billion adults over the age of 25 were affected by overweight and obesity. The countries with the largest number of people living with overweight and obesity were China, India, and the United States. However, in terms of proportion, many countries in Oceania, North Africa, and the Middle East observe an extremely high prevalence of overweight and obesity, where more than 85% of the adult population experience these conditions.

If no action is taken, we forecast that by 2050, 3.8 billion adults globally will experience overweight and obesity. Some of the largest increases are expected to be observed in Africa and Asia.

How many children and adolescents are currently overweight or obese, and what do you forecast the numbers to be by 2050?

Dr. Jessica Kerr

So, we found that currently there’s around 490 million children and adolescents across the world living with either overweight or obesity. So that is a doubling in the prevalence since 1990, and a tripling in the prevalence of obesity alone. So, from now into the future, we’re predicting really rapid increases in these trajectories, especially in obesity, throughout every region of the world.

And this means by around 2050, that about one-third of the world’s population of children and adolescents will be living with overweight or obesity. So that’s 390 million children and adolescents living with overweight, and about 360 million living with obesity.

What impact can obesity have on children and adolescents in particular?

Dr. Jessica Kerr

So, we commonly think of obesity as a disease just affecting adulthood. And although it is true that there are many serious diseases in the adulthood years associated with obesity, it can also have immediate impacts on children and adolescents now. So, it can negatively impact their school engagement, their community participation, their mental health.

And it can also have early impacts on their physical health as well, such as fatty liver disease, type 2 diabetes, hypertension, and the early development of fertility problems. At the level of society, the problems with these really high numbers predicted of overweight and obesity, means that will have health and economic impacts, and society impacts as well. So, it means that our future workforce will be working with a really high disease burden that will impact our health systems. And the economic impacts are predicted to exceed 3% of the world’s GDP by 2060 as well.

Which regions of the world may be most affected by the increases in obesity?

Dr. Marie Ng

In the last 30 years, the most rapid increase in obesity prevalence were observed in North Africa and the Middle East. The obesity prevalence in this region among males more than tripled, rising from 9.5% in 1990 to 36.2% in 2021. Female prevalence in the region also more than doubled, increasing from 23.7% in 1990 to 51.1% in 2021, in the next 30 years.

We forecast that 24 countries, primarily in Asia and sub-Saharan Africa, will serve increasing obesity prevalence by over 100%, with nearly a 12:45 third of the adults having obesity.

In what way are younger populations affected differently by the increase in overweight and obesity?

Dr. Jessica Kerr

So, globally and throughout many regions of the world, such as Africa and Asia, it was actually the younger population of children and young adolescents, aged between 5 and 14, who were expected to fare the worst in this obesity crisis. And that was particularly true for young boys. So, by 2050, we are expecting more young boys to be living with obesity rather than overweight.

However, we also pinpointed adolescent girls as another priority population, and this is because in many regions of the world they are already living with obesity predominance, and this includes adolescent girls throughout Australasia, North America, the Middle East and North Africa, Latin America, and sub-Saharan Africa. So, it’s really important that we target these girls and help them with interventions to have a healthy weight by the time they’re into their reproductive years, because we know that obesity can be transmitted inter-generationally.