Key Facts
As of 2022, one in eight people worldwide lives with obesity. Since 1990, adult obesity rates have more than doubled, and adolescent obesity has quadrupled. In 2022, 2.5 billion adults (18 years and older) were overweight, and among them, 890 million were classified as obese. Overall, 43% of adults were overweight, and 16% were obese. By 2024, the number of overweight children under the age of five is projected to reach 35 million. In 2022, over 390 million children and adolescents aged 5 to 19 were overweight, including 160 million with obesity.
Definitions
Overweight and Obesity
Overweight and obesity refer to abnormal or excessive fat accumulation that may impair health. They are typically diagnosed using Body Mass Index (BMI), calculated as weight in kilograms divided by height in meters squared (kg/m²). Although BMI is a practical screening tool, other measurements like waist circumference are also valuable in clinical assessments.
Adults
For adults, WHO defines:
Overweight as a BMI ≥ 25
Obesity as a BMI ≥ 30
Children Under 5
For children under 5:
Overweight is defined as weight-for-height more than 2 standard deviations above the WHO Child Growth Standards median
Obesity is more than 3 standard deviations above
Children and Adolescents Aged 5–19
Overweight is defined as BMI-for-age more than 1 standard deviation above the WHO Growth Reference median
Obesity is more than 2 standard deviations above
Global Trends
In 2022, 43% of adults aged 18 and over were overweight, compared to 25% in 1990. Obesity affected 16% of adults globally, more than double the rate in 1990. Regional differences are stark, with adult overweight rates ranging from 31% in WHO’s South-East Asia and Africa regions to 67% in the Americas.
Among children under five, 35 million were overweight in 2024. While this was once a problem mainly in high-income countries, it now increasingly affects low- and middle-income nations. In Africa, the number of overweight children under five increased by nearly 12.1% since 2000. In 2024, almost half of all overweight or obese children under five were in Asia.
Among 5–19-year-olds, overweight prevalence rose from 8% in 1990 to 20% in 2022. Obesity in this age group rose from 2% (31 million children) to 8% (160 million) over the same period.
Causes
The fundamental cause of overweight and obesity is an energy imbalance between calories consumed and expended. However, most obesity cases are the result of a complex interplay between environmental, genetic, behavioral, and psychological factors. In some individuals, obesity can be attributed to specific causes such as medication, underlying diseases, genetic syndromes, or reduced mobility.
Obesogenic environments—characterized by limited access to affordable healthy foods, lack of safe spaces for physical activity, and weak health policies—significantly increase the risk of obesity at the individual and population levels. Furthermore, the absence of strong public health systems that can identify and manage early signs of weight gain exacerbates the problem.
Health Consequences
Obesity and overweight are major risk factors for noncommunicable diseases (NCDs), including cardiovascular diseases, type 2 diabetes, certain cancers, neurological conditions, and chronic respiratory and digestive disorders. In 2021 alone, suboptimal BMI contributed to 3.7 million NCD-related deaths globally.
Among children and adolescents, obesity increases the risk of early onset of NCDs. It is also associated with social stigma, discrimination, bullying, poor academic performance, and reduced quality of life. Children with obesity are likely to remain obese into adulthood and are at greater risk of developing severe health issues later in life.
The economic burden of obesity is equally concerning. Without intervention, the global cost of overweight and obesity is expected to reach $3 trillion annually by 2030 and exceed $18 trillion by 2060.
The Double Burden of Malnutrition
Many low- and middle-income countries are now facing a dual burden of malnutrition: the coexistence of undernutrition and obesity. Within the same country, community, or even household, it is common to see both forms of malnutrition.
Children in these countries often experience undernutrition early in life and are later exposed to energy-dense, nutrient-poor foods high in sugar, fat, and salt—foods that are inexpensive but unhealthy. This dietary transition, coupled with limited physical activity, contributes to rising obesity rates without resolving undernutrition.
Prevention and Management
Overweight and obesity—as well as related NCDs—are largely preventable. Prevention can begin as early as the prenatal stage and continue throughout life. Effective strategies include:
Maintaining appropriate weight gain during pregnancy
Exclusive breastfeeding for the first six months and continued breastfeeding until at least two years of age
Promoting healthy diets, physical activity, sleep hygiene, and reducing screen time among children
Limiting consumption of sugary drinks and high-energy foods
Encouraging healthy lifestyles, including good nutrition, regular physical activity, emotional regulation, and avoidance of tobacco and alcohol
Health professionals have a crucial role to play. They must:
Monitor BMI and other relevant health indicators
Offer counseling on diet and physical activity
Provide integrated obesity care including behavioral, medical, and surgical interventions
Screen for comorbidities such as high blood pressure, lipid disorders, diabetes, and mental health issues
Systemic and Policy Interventions
Obesity is a societal issue that requires coordinated action across multiple sectors. Sustainable solutions must come from environments and policies that make healthy choices the easy and affordable ones.
Necessary interventions include:
Policies to improve access to nutritious foods through pricing, labeling, and marketing restrictions
Building health systems that can prevent, diagnose, and manage obesity effectively
Urban planning and poverty reduction strategies that promote healthy lifestyles
Food industry participation to reduce unhealthy ingredients in processed foods and promote healthy options
WHO’s Response
WHO has long acknowledged the urgency of addressing obesity. Member States have committed to global nutrition and NCD targets, including halting the rise in childhood overweight and adult obesity by 2025.
At the 75th World Health Assembly in 2022, Member States adopted new recommendations for preventing and managing obesity and approved WHO’s Acceleration Plan to Stop Obesity. This plan aims to support national implementation, create political momentum, and establish accountability at both national and global levels.
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