An international large-scale study involving the University of Granada (UGR) examines obesity trends since the 1980s and reveals that the increase has slowed, stabilized, and even reversed in many countries, though it is still rising in developing nations
More than 1,900 researchers participated in this analysis, which utilized data from 232 million people across 200 countries and territories
A study led by researchers at Imperial College London, through the NCD Risk Factor Collaboration (NCD-RisC), and published in the prestigious journal Nature, has analyzed more than four decades of global obesity data, covering the period from 1980 to 2024.
Scientists from the University of Granada participated in this study by providing data on very young children in Spain who were part of the PREFIT experiment, a multicenter cohort study coordinated by the PROFITH research group at the University Joint Institute for Sport and Health at the UGR.
PREFIT collected data on physical fitness and obesity levels in preschool-aged children (ages three to five) across 10 Spanish regions. This study was conducted collaboratively within the EXERNET network (Exercise and Health Research Network) and involved researchers from 10 universities across Spain, including Granada, Almería, and Cádiz (south); Cuenca and Madrid (central); Castellón de la Plana (east); Zaragoza and Vitoria (north); and the two main islands, Mallorca and Gran Canaria.
The results come as experts from around the world gather this month at the European Congress on Obesity (ECO 2026) in Istanbul and offer a more optimistic picture of progress than had previously been reported.
Francisco B. Ortega, a professor at the Faculty of Sports Sciences and the iMUDS research center at the University of Granada, and principal investigator of the PREFIT study, explains that “it is important to contribute data from Spain to this large-scale study to better understand obesity trends in our country and how they compare with the rest of Europe and the world.” In fact, Spain has been among the countries with the highest obesity rates in Europe in recent years, but the parameters of this new analysis indicate that the rise in obesity has plateaued for both genders and across different age groups. For girls and boys, the stabilization has occurred at a prevalence of 10% and 14%, higher than in many other countries that have also plateaued in this age group. For women and men, the plateau is established at a moderate prevalence of 13% and 18%, and may have begun to decline.”
Cristina Cadenas, data collection coordinator for the PREFIT project, emphasizes that “although obesity trends have improved in Spain, the total percentage of people living with overweight or obesity across different age groups remains very high, and therefore it is necessary to continue investing in strategies to promote physical activity and healthy eating to mitigate the many negative effects that excess weight has on individuals and society.”
The main findings of this global scientific project indicate that the rise in obesity rates has slowed or stabilized in most high-income countries, despite rapid increases in the late 20th century, first slowing among school-age children and then among adults, approximately a decade later. In some high-income nations (including France, Italy, and Portugal), rates may even have begun to decline.
According to the researchers, these latest findings suggest that previous claims of a “global obesity epidemic” are likely an oversimplification and mask the enormous diversity observed among countries, which may be driven by a range of factors, particularly the availability and affordability of healthy foods.
However, they emphasize that the prevalence of obesity continues to rise in many low- and middle-income countries, particularly in Africa, Asia, Latin America, and the Pacific Islands and the Caribbean.
The experts state that, “by focusing on the rate of change in obesity over time, rather than just on prevalence, we can learn where and when urgent action is needed, including robust health, physical activity, and nutrition policies to help nations adapt and manage public health during economic, technological, and nutritional transitions.”
Professor Majid Ezzati of the School of Public Health at Imperial College London and academic director of Imperial Global Ghana, who led the analysis, says: “We have been analyzing obesity trends for decades and have shown that, overall, it has increased, with more people affected by overweight and obesity. However, this latest analysis suggests that the rate of obesity growth is slowing and stabilizing, and may even be reversing in many countries. This offers a more optimistic picture of progress and challenges the widely accepted view that we are experiencing a global obesity epidemic, which may be an oversimplification of the diversity of the situation across different countries. By focusing on the rate of change, we can better understand and compare nations’ progress in preventing and combating obesity—not just where we are now, but where we are headed.”
“Now we need to find out why some countries are doing much better than others and apply those lessons to prevent obesity from rising. Ultimately, this article shows that the trend toward obesity is not inevitable, and that it is possible for policymakers to intervene to halt and even reverse the rise in obesity,” says Majid Ezzati.
Dr. Jennifer Baker, president-elect of the European Association for the Study of Obesity and of the Center for Clinical Research and Prevention at Copenhagen University Hospital, says: “There has been real progress on childhood obesity in parts of Europe and around the world, but we cannot become complacent. Levels remain too high, and on a global scale, the situation is markedly uneven, with continued increases in some countries.”
Previous reports on the global state of obesity, including those produced by NCD-RisC in collaboration with the World Health Organization (WHO), typically compare obesity prevalence over decades. According to the researchers, while this provides valuable information, the approach can make it difficult to track progress in controlling obesity, especially recent changes that reflect policy innovation.
In the latest analysis, the scientists used the rate of change in the obesity rate as a key measure: calculated as the absolute annual change in obesity prevalence. This was documented in annual percentage points.
Using this method, they were able to provide a clearer picture of where increases in obesity are accelerating, stabilizing, or reversing.
The team analyzed weight and height measurements from more than 232 million people aged five and older (70 million people aged five to 19 and 162 million aged 20 and older), representing 200 countries and territories.
More than 1,900 researchers contributed to the study, which analyzed body mass index (BMI) to understand how obesity rates have changed globally from 1980 to 2024. Obesity is defined as a BMI ≥30 kg/m² in adults and a BMI >2 standard deviations (SD) above the median of the WHO growth reference for children and adolescents. Obesity estimates are adjusted for differences in how the population is distributed across different ages, using a process called age standardization.
Among the key findings that have emerged is that improvements in high-income countries are typically observed first among children and adolescents, followed approximately a decade later by adults. In most high-income Western countries, the rise in obesity among children occurred before the turn of the millennium, with this trend slowing, stabilizing, and even declining slightly compared to the year 2000.
Denmark experienced the earliest documented slowdown (around 1990), followed by other European countries such as Iceland, Switzerland, Belgium, and Germany, all during the 1990s. By the mid-2000s, rising obesity rates among school-age children and adolescents in most high-income countries began to stabilize and, in some, even decline. Exceptions were seen among children in Australia, Finland, and Sweden, where obesity increased steadily or at an accelerated rate.
However, this stabilization has occurred at very different national prevalence levels across countries. In Western European nations and in Japan, the rise in obesity stabilized or reversed when prevalence was below 10% of the school-age population (that is, where fewer than one in ten children were obese). In comparison, in the United States and New Zealand, obesity stabilized when levels were much higher, between 19% and 23% of the school-age population (that is, where up to one in four schoolchildren was obese). The same trend was observed among adults.
In contrast to these signs of progress, the analysis also highlights that obesity continues to rise—and is even accelerating—in most low- and middle-income countries.
This divergence from the progress observed in high-income countries highlights growing global inequalities in nutrition, physical activity, and health. Experts emphasize the need for tailored public health policies to address the widening gap, including those focused on the availability and affordability of healthy foods for countries and communities that currently cannot afford or access them.
Over the past decade, new obesity medications have become widely available, including GLP-1 receptor agonists (such as liraglutide and semaglutide). The researchers state that the introduction of these drugs does not yet explain the changes observed in their study, but they add that they will likely play an important role in future trends, especially if access is improved.
Professor Ezzati explains: “At this stage, it is probably too early to say whether GLP-1 drugs have had a direct impact on entire populations, even if they are beneficial for the patients who use them. The goal should be to make them more affordable for everyone who needs them worldwide”.
Nature
Case study
People
The rise in obesity is plateauing in developed countries and accelerating in developing countries
13-May-2026