A sweeping new analysis of global body weight trends suggests the world’s obesity crisis is splintering into divergent paths, with growth slowing or stabilizing in many wealthy countries while continuing to climb in most low- and middle-income nations. The study, led by the NCD Risk Factor Collaboration (NCD-RisC) in partnership with the World Health Organization, drew on 4,050 population surveys and pooled measurements from more than 232 million people across 200 countries and territories between 1980 and 2024. Its authors report that while obesity remains more prevalent today than at the end of the 20th century, the pace and direction of change vary substantially across populations, sexes, and age groups, indicating the epidemic is entering a new phase defined by socioeconomic divide. “The rise is not inevitable,” and in the “vast majority of low- and middle income countries, it’s going up steadily or even accelerating,” said Professor Majid Ezzati, according to Nature.
Wealthy countries
In nations where obesity surged earliest—largely high-income Western countries—the steep rise began flattening in the 1990s and has since slowed, with a notable sequence: progress first emerged among children and adolescents, then followed in adults roughly a decade later.
In Western Europe, adult obesity has stabilized between 11% and 23%, and among children and adolescents between 4% and 15%, with some countries such as Spain, Italy, France, and Portugal showing a negative growth rate in adult obesity by 2024. Researchers hypothesize that gradual economic shifts and rising nutritional awareness—especially among higher-income and more educated groups—have helped drive this slowdown, though it often coincided with widening internal inequalities. They also note that changes in the food environment and opportunities for physical activity likely affected younger cohorts first, before influencing adult populations. While new anti-obesity drugs have captured attention, the study cautions that their impact on national obesity trends will not be clear for five to ten years and that it is too early to attribute the observed slowdowns to pharmaceutical interventions.
In many low- and middle-income countries across Asia, Africa, and Latin America, adult and childhood obesity continue to rise, in some cases at the fastest rates recorded to date. Several countries in Central Europe, including Romania and Czechia, and in Latin America, notably Brazil, have seen adult obesity reach 30%–40%. Brazil exemplifies the continuing climb: overall adult prevalence now exceeds 30%, and among women the rate rose from 9.3% in 1980 to 34.9% in 2024, an increase of 25.6 percentage points, with no sign of stabilization.
The study points to a complex set of drivers—rapid urbanization, expanding access to ultra-processed foods, work mechanization, more sedentary lifestyles, social inequality, and persistent barriers to healthy foods. The authors highlight the particular role of ultra-processed products, noting their high energy density, hyperpalatability, and ease of overconsumption, which together can promote passive caloric intake beyond energy needs.
United States
In the US, obesity appears to have plateaued among children and adolescents but continues to climb in adults, though at a slower rate than before; prevalence remains among the world’s highest and the highest in high-income Western countries, ranging from 20% to 23% for children and 40% to 43% for adults, according to STAT.
Researchers note that excess weight has been rising for 40–45 years, elevating the risk of cancer, cardiovascular, metabolic, and neurological diseases. Gaining substantial weight in adulthood can raise cancer risk up to five-fold, even for those who were lean in their teens, underscoring the importance of avoiding rapid weight increases over just a few years. While some experts characterized the finding that obesity has increased in many places—and still rises in most—as unsurprising, others questioned the emphasis on year-to-year changes in BMI or prevalence as a lens for interpreting trajectories. The authors argue that recognizing where and for whom the curves are bending could clarify the forces reshaping diets and activity patterns and inform targeted programs and policies to prevent and curb obesity’s rise.