Alarming Projection: By 2035, more than half of the global population will be obese

By Benedette Cuffari, M.Sc.Mar 2 2023Reviewed by Danielle Ellis, B.Sc.

Being overweight or obese is defined as a body mass index (BMI) value exceeding 25 kg/m². By 2035, the World Obesity Atlas predicts that over 4 billion people worldwide will be considered obese, which amounts to over 51% of the global population.

Study: World Obesity Atlas 2023. Image Credit: Fuss Sergey / Shutterstock.com

Obesity and low-income nations

Every country throughout the world is affected by obesity; however, some lower-income countries have experienced the most staggering rises in their obesity rates over the past decade.

Kiribati, a Pacific Island nation considered to be one of the least developed countries in this region, is expected to have the highest rate of adult obesity in the world by 2035 at 67%. This is slightly higher than the predictions for Samoa, French Polynesia, and Micronesia, with 66%, 65%, and 64% of adult populations expected to be obese by 2035, respectively.

Children and adolescents residing in low-income countries are at the greatest risk of becoming obese by 2035. In fact, the Atlas predicts that the 2020 obesity rates of 4% for girls and 2% for boys in low-income countries will rise to 13% and 6%, respectively, by 2035. Comparatively, obesity previously affected 5% and 14% of adult men and women in low-income nations, which is expected to increase to 11% and 26%, respectively, by 2035.

Globalization and the rise in ultra-processed foods worldwide have increased the vulnerability of lower-income countries to obesity. These factors have also led to a greater reliance on plastic-based products and, as a result, plastic waste generation, further increasing the risk of these populations being exposed to potentially obesogenic pollutants.

Economic impacts

Current estimates indicate that obesity and being overweight will cost the global economy over USD 4 trillion of potential income in 2035.

The costs associated with an increasingly overweight population are based on how high BMI values contribute to the development of 38 diseases. These major comorbidities of obesity include various types of cancer, hypertension, cardiovascular disease, diabetes, and liver and kidney disease.

Aside from the costs that arise when dealing with these health conditions, unemployment, long-term disability, and early retirement are also associated with obesity and its comorbid health conditions. Importantly, the global economic impact of obesity estimated by the World Obesity Atlas did not consider how these factors may also increase national costs, thus indicating that the growing obesity epidemic will likely be more expensive than current estimates have predicted.

How COVID-19 worsened obesity

Throughout the coronavirus disease 2019 (COVID-19) pandemic, national lockdowns significantly restricted the ability of many people to leave their homes. As a result, dietary and sedentary behaviors often associated with weight gain increased.

These behaviors included, but are not limited to, reduced physical activity levels and greater daily consumption of processed foods, particularly among children. For example, one study conducted in China that included over 10,000 adolescents and young adults found that the prevalence of obesity increased from 10% to 12.5%, whereas the overweight prevalence similarly increased from 21% to 25%.

Previous studies have consistently demonstrated that population-level weight gain is difficult to prevent or reverse. Thus, the rapid rise in weight gain due to the COVID-19 pandemic may lead to even higher obesity, and overweight levels than current estimates have accounted for.

Taking action on obesity

Despite the numerous downstream health and economic impacts associated with an increasingly obese population, there remains a lack of federal and international funding that prioritizes the prevention and treatment of obesity. Thus, there is an urgent need to increase public financing for related health priorities, which can be in the form of a tax on sugar-sweetened beverages and addressing some of the numerous environmental factors that can similarly increase the risk of obesity.

In an effort to accelerate global action on obesity, the International Classification of Disease (ICD) updated the definition of obesity in 2022. Furthermore, the World Health Organization (WHO) also provided new recommendations on how to prevent and manage obesity, which can serve as foundations for both global and national action plans.

These efforts align with the priority actions previously incorporated into the World Obesity Federation ROOTS framework published in 2020. Aside from the aforementioned priorities, this framework emphasizes the importance of investing in healthcare workers and exceptionally well-trained professionals equipped to prevent, manage, and treat obesity to ensure the availability of high-quality care to high-risk patients.