Key facts
- In 2024, 1 in 7 people (1.1 billion) in the world were living with obesity.
- Worldwide adult obesity has more than doubled since 1990, and adolescent obesity has quadrupled.
- In 2024, 45% of adults 18 years and over (2.6 billion) were overweight. Of these, 940 million were living with obesity (16% of all adults).
- In 2024, 35 million children under the age of 5 were overweight.
- In 2024, 400 million children and adolescents aged 5–19 years were overweight, including 170 million who were living with obesity.
Overview
Obesity is a chronic disease affecting 1.1 billion people worldwide (1).
It is driven by complex interactions between environmental, social, biological and behavioural determinants. The global rise of obesity is contributing to the increasing burden of type 2 diabetes, cardiovascular disease, liver and kidney disease, and several cancers (3).
Obesity affects people in all regions of the world and has risen alongside improvements in food security, socioeconomic development and major changes in diets, physical activity patterns, and broader social and behavioural norms. Together, these shifts have created environments that promote unhealthy weight gain and make prevention and treatment more difficult. As a result, obesity has become a major global public health challenge.
A diagnosis of overweight or obesity is made by measuring a person’s weight and height and by calculating their body mass index (BMI): weight (kg)/height² (m²). Other measures, such as waist circumference, can also be used to identify overweight or obesity.
The BMI categories for defining overweight and obesity vary by age and sex for adults, adolescents, children and infants.
Definition of overweight and obesity
WHO defines overweight and obesity as outlined below.
Adults
- overweight is a BMI greater than or equal to 25; and
- obesity is a BMI greater than or equal to 30.
Children
For children, age needs to be considered when defining overweight and obesity.
Children and adolescents aged 5–19 years
- overweight is BMI-for-age greater than 1 standard deviation above the WHO Growth Reference median; and
- obesity is greater than 2 standard deviations above the WHO Growth Reference median.
Charts and tables: WHO growth reference for children aged between 5–19 years
Children under 5 years of age
- overweight is weight-for-height greater than 2 standard deviations above WHO Child Growth Standards median; and
- obesity is weight-for-height greater than 3 standard deviations above the WHO Child Growth Standards median.
Charts and tables: WHO child growth standards for children aged under 5 years
Prevalence of overweight and obesity
In 2024, 2.6 billion adults aged 18 years and older were overweight, including 940 million adults who were living with obesity (1). This corresponds to 45% of adults aged 18 years and over (44% of men and 45% of women) who were overweight; this is an increase from 1990, when 25% of adults aged 18 years and over were overweight. Prevalence of overweight varied by region, from 32% in the WHO South-East Asia Region and the African Region to 68% in the Region of the Americas.
About 16% of adults aged 18 years and older worldwide were living with obesity in 2024. The worldwide prevalence of obesity more than doubled between 1990 and 2024.
In 2024, an estimated 35 million children under the age of 5 years were overweight (2). Once considered a high-income country problem, overweight is on the rise in low- and middle-income countries. In Africa, the number of overweight children under 5 years has increased by nearly 12% since 2000. Almost half of the children under 5 years who were overweight in 2024 lived in Asia.
In 2024, 400 million children and adolescents aged 5–19 years were overweight. The prevalence of overweight (including obesity) among children and adolescents aged 5–19 has risen dramatically from just 8% in 1990 to 20% in 2024. The rise has occurred similarly among both boys and girls: in 2024, 19% of girls and 21% of boys were overweight.
While just 2% of children and adolescents aged 5–19 were living with obesity in 1990 (31 million young people), by 2024, 8% of children and adolescents were living with obesity (170 million young people).
Obesity prevalence is currently increasing faster in low- and middle-income countries and in many rural populations worldwide than in the urban populations and high-income countries it was once associated with.
Causes of overweight and obesity
Obesity is a chronic disease resulting from complex interactions between environmental and psychosocial influences and biological susceptibility.
The global health challenge of obesity is driven by increasingly obesogenic environments that limit access to healthy, affordable and sustainably produced foods; constrain opportunities for safe physical activity; and are shaped by market forces and inadequate legal and regulatory frameworks. These drivers are compounded by insufficient health system capacity to prevent, identify and manage obesity early. Addressing the challenge requires coordinated action across food systems, the built environment, regulatory and fiscal policies, and health systems to strengthen prevention, early diagnosis and multimodal chronic care including treatment, care and ongoing support.
Obesity is characterized by dysregulation of neurobiological and metabolic pathways involved in appetite, energy balance and adipose tissue function, with genetic variation influencing individual susceptibility.
Health and economic consequences
The health risks caused by overweight and obesity are increasingly well documented and understood.
In 2023, higher-than-optimal BMI caused an estimated 3.7 million deaths by increasing the number of deaths from diseases such as cardiovascular diseases, diabetes and cancers (3).
Overweight and obesity in childhood and adolescence adversely affect physical, mental and social well-being and should be identified and addressed as early as possible. They are associated with stigma, discrimination, bullying, poorer quality of life and impaired school performance. Without timely intervention, obesity often persists into adulthood, increasing the risk and accelerating the onset of noncommunicable diseases (NCDs), including type 2 diabetes and cardiovascular disease. Early prevention and effective treatment can reduce these long-term health risks and improve outcomes across the life course.
The economic impact of obesity is also important. If nothing is done, the global costs of overweight and obesity are predicted to reach US$ 3 trillion per year by 2030 and more than US$ 18 trillion by 2060 (4).Facing a double burden of malnutrition
Many low- and middle-income countries face a so-called double burden of malnutrition.
While these countries continue to deal with the problems of infectious diseases and undernutrition, they are also experiencing a rapid upsurge in noncommunicable disease risk factors such as obesity and overweight.
Children in low- and middle-income countries are more vulnerable to inadequate pre-natal, infant and young child nutrition. At the same time, the children are exposed to high-fat, high-sugar, high-salt, energy-dense and micronutrient-poor foods, which tend to be lower in cost but also lower in nutrient quality. These dietary patterns, in conjunction with lower levels of physical activity, result in sharp increases in childhood obesity while undernutrition issues remain unsolved.
Prevention and management
Overweight and obesity, as well as their related noncommunicable diseases, are largely preventable and manageable.
At the individual level, the risk of overweight and obesity can be reduced through preventive actions taken throughout the life course, from before conception through older age. These include:
- achieving a healthy weight before pregnancy and ensuring appropriate weight gain during pregnancy;
- practising exclusive breastfeeding for the first 6 months of life and continuing breastfeeding up to 2 years of age or beyond;
- supporting healthy eating, physical activity, good sleep, and limiting sedentary behaviour and screen time throughout childhood and adolescence;
- limiting the consumption of sugar-sweetened beverages and energy-dense, nutrient-poor foods;
- eating a healthy diet rich in fruits, vegetables, legumes, whole grains, and nuts, while limiting foods high in fats, sugars, and salt;
- engaging in regular physical activity throughout life;
- getting adequate sleep and supporting emotional well-being; and
- avoiding tobacco use and the harmful use of alcohol.
Health practitioners need to:
- routinely assess weight status and identify overweight and obesity early;
- provide evidence-based counselling on healthy diet, physical activity, sleep and other healthy behaviours to all;
- assess obesity-related complications, comorbidities, hypertension, diabetes, disability, mental health and other NCD risk factors;
- deliver or refer people with obesity to comprehensive, person-centred multimodal chronic care, including behavioural interventions, nutritional counselling, psychological support, pharmacological treatment, and metabolic and bariatric surgery, as appropriate;
- develop individualized, long-term care plans with regular follow-up to improve cardiometabolic health, support sustained weight management, reduce obesity-related complications, and improve quality of life; and
- monitor treatment response, service coverage, quality of care and long-term health outcomes of treatment.
Key policy actions include:
- structural, fiscal and regulatory measures to create healthy food environments that make healthier food options available, affordable and desirable;
- actions across food systems, education, urban planning, transport and social protection to address the wider determinants of health and promote healthy eating and physical activity throughout the life course; and
- health system responses that strengthen primary health care to identify risk, prevent, diagnose, treat and manage obesity and NCD through integrated, person-centred multimodal chronic care programmes.
The food industry can play a significant role in promoting healthy diets by:
- reducing the fat, sugar and salt content of processed foods;
- ensuring that healthy and nutritious choices are available and affordable to all consumers;
- restricting marketing of foods high in sugars, salt and fats, especially those foods aimed at children and teenagers; and
- ensuring the availability of healthy food choices and supporting regular physical activity practice in the workplace.
WHO response
WHO has recognized the urgent need to tackle the global health obesity challenge. WHO Member States have called for accelerated global action to address the double burden of malnutrition, including through effective prevention and management of obesity.
WHO has developed a series of best buys for NCD prevention and management that are feasible, evidence-based and cost effective. The economic return on investment of healthy diet-related best buys is estimated at 14 times for every unit of currency invested.
Almost 9 out of 10 countries have adopted policy goals towards obesity reduction. Higher-income countries more often have adopted specific healthy diet-related best buys policies, and on a mandatory basis, than lower-income countries.
In 2022, Member States endorsed the WHO Acceleration Plan to Stop Obesity. It supports countries in transforming food and urban environments, creating knowledge, motivation and skills among the general population and people living with obesity, and strengthening health systems to expand equitable access to obesity prevention and treatment services. It has expanded to 34 frontrunner countries, representing 1.3 billion people and one third of the global population living with obesity.
In December 2025, WHO published the guideline on the use of glucagon-like peptide-1 (GLP-1) therapies for the treatment of obesity in adults. It supports their safe, equitable and appropriate inclusion as one component of multimodal chronic obesity care, alongside behavioural, nutritional, psychological and other evidence-based interventions.
WHO is working alongside countries to prepare health systems to scale up comprehensive obesity chronic care programmes and support monitoring of service coverage, quality of care and health outcomes.
References
1. NCD Risk Factor Collaboration (NCD-RisC). Obesity rise plateaus in developed nations and accelerates in developing nations. Nature 653, 510–518 (2026). https://doi.org/10.1038/s41586-026-10383-0
2. United Nations Children’s Fund (UNICEF), World Health Organization, International Bank for Reconstruction and Development/The World Bank. Levels and trends in child malnutrition: Key Findings of the 2025 Edition of the Joint Child Malnutrition Estimates. Geneva: World Health Organization; 2025
3. GBD 2023 Disease and Injury and Risk Factor Collaborators. “Burden of 375 diseases and injuries, risk-attributable burden of 88 risk factors, and healthy life expectancy in 204 countries and territories, including 660 subnational locations, 1990–2023: a systematic analysis for the Global Burden of Disease Study 2023”. Lancet. 2025; 406:10513 1873.
4. Okunogbe et al., “Economic Impacts of Overweight and Obesity.” 2nd Edition with Estimates for 161 Countries. World Obesity Federation, 2022.