Body weight is classified using the Body Mass Index (BMI). BMI is calculated from the relationship between body weight and height:

BMI = weight (kg) / height² (m²)

According to the WHO (2000) classification, body weight is categorized as follows:

You can easily calculate your BMI using a BMI calculator.

Large studies involving more than one million participants have shown that mortality follows a U-shaped relationship with BMI. The lowest risk of death is observed in individuals with a BMI between 25 and 27 kg/m². Below a BMI of 25, the risk of dying from other diseases increases. Above a BMI of 25, the risk of death attributable to the effects of obesity becomes progressively greater.

In addition to BMI, body fat distribution is a major determinant of metabolic and cardiovascular health risk. In particular, visceral fat mass is strongly correlated with cardiovascular risk and obesity-related complications. Waist circumference provides a practical estimate of visceral fat accumulation. However, reducing waist circumference through liposuction does not reduce cardiovascular risk, as only visceral adipose tissue, rather than subcutaneous fat, is associated with increased cardiovascular risk.

* The risk of other clinical health problems is increased.

According to the Organisation for Economic Co-operation and Development (OECD), the prevalence of obesity (BMI > 30 kg/m²) among individuals aged over 15 years in Germany was 23.6% in 2016. In the United States, the prevalence was 40%, while the average across all OECD countries was approximately 20%. Among 15-year-old children, 16% were already overweight.

*Approximate estimates based on national surveys; definitions and survey methods may differ from OECD data.

Key observations:

• The United States has the highest prevalence of adult obesity, with approximately 40% of adults (≥15 years) having a BMI ≥30 kg/m².
• Germany (23.6%) is above the OECD average (~20%).
• India has a substantially lower prevalence of adult obesity (approximately 5%), although rates are increasing rapidly in urban populations.
• Among adolescents, overweight prevalence is highest in the United States, followed by Germany/OECD countries, while India has the lowest prevalence among the regions compared.