OECD Factbook 2011-2012: Economic, Environmental and Social Statistics
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branch Health
branch Risk factor
    branch Overweight and obesity

The rise in overweight and obesity is a major public health concern. Obesity is a known risk factor for numerous health problems, including hypertension, high cholesterol, diabetes, cardiovascular diseases, respiratory problems (asthma), musculoskeletal diseases (arthritis) and some forms of cancer. At an individual level, several factors can lead to obesity, including excessive calorie consumption, lack of physical activity, genetic predisposition and disorders of the endocrine system.

Because obesity is associated with higher risks of chronic illnesses, it is linked to significant additional health care costs. There is a time lag between the onset of obesity and related health problems, suggesting that the rise in obesity over the past two decades will mean higher health care costs in the future. Mortality also increases sharply once the overweight threshold is crossed.


Overweight and obesity are defined as excessive weight presenting health risks because of the high proportion of body fat. The most frequently used measure is based on the body mass index (BMI), which is a single number that evaluates an individual's weight in relation to height (weight/height2, with weight in kilograms and height in metres). Based on the WHO classification, adults with a BMI between 25 and 30 are defined as overweight, and those with a BMI over 30 as obese.


The BMI classification may not be suitable for all ethnic groups, who may be exposed to different levels of health risk for the same level of BMI. The thresholds for adults are also not suitable to measure overweight and obesity among children.

For most countries, overweight and obesity rates are self-reported through estimates of height and weight from population-based health interview surveys. However, around one-third of OECD countries derive their estimates from health examinations. These differences limit data comparability. Estimates from health examinations are generally higher and more reliable than from health interviews.

The following countries use measured data: Australia, Canada, Chile, the Czech Republic, Finland, Ireland, Japan, Korea, Luxembourg, Mexico, New Zealand, the Slovak Republic, the United Kingdom and the United States.


Based on latest available surveys, more than half (50.3%) of the adult population in the OECD report that they are overweight or obese. Among those countries where height and weight were measured, the proportion was even greater, at 55.8%. The prevalence of overweight and obesity among adults exceeds 50% in no less than 19 of 34 OECD countries. In contrast, overweight and obesity rates are much lower in Japan and Korea and in some European countries (France and Switzerland), although even in these countries rates are increasing.

The prevalence of obesity, which presents even greater health risks than overweight, varies tenfold among OECD countries, from a low of 4% in Japan and Korea, to 30% or more in the United States and Mexico. Across the entire OECD region, 17% of the adult population are obese. Average obesity rates among men and women are similar, although there are disparities in some countries. In Chile, Turkey and Mexico, a greater proportion of women are obese, whereas in the Russian Federation, Luxembourg and Spain men are more likely to be obese.

Obesity prevalence has more than doubled over the past 20 years in Australia and New Zealand, and increased by half in the United Kingdom and the United States. Some 20-24% of adults in Australia, Canada, the United Kingdom and Ireland are obese, about the same rate as in the United States in the early 1990s. Obesity rates in many western European countries have also increased substantially over the past decade. The rapid rise occurred regardless of where levels stood two decades ago. Obesity almost doubled in both the Netherlands and the United Kingdom, even though the current rate in the Netherlands is around half that in the United Kingdom.

In most countries, the rise in obesity has affected all population groups, regardless of sex, age, race, income or education level, but to varying extents. Evidence from a number of countries (Australia, Austria, Canada, France, Italy, Korea, Spain, the United Kingdom and the United States) indicates that obesity tends to be more common among individuals in disadvantaged socio-economic groups, especially women. There is also a relationship between the number of years spent in full-time education and obesity, with the most educated individuals displaying lower rates. Again, the gradient in obesity is stronger in women than in men.



Further information
Analytical publications
  • OECD (2010), Obesity and the Economics of Prevention: Fit not Fat, OECD Publishing.
  • Sassi, F. et al. (2009), “Education and Obesity in Four OECD Countries”, OECD Health Working Papers, No. 46.
  • Sassi, F. et al. (2009), “Improving Lifestyles, Tackling Obesity: The Health and Economic Impact of Prevention Strategies”, OECD Health Working Papers, No. 48.
  • Sassi, F. et al. (2009), “The Obesity Epidemic: Analysis of Past and Projected Future Trends in Selected OECD Countries”, OECD Health Working Papers, No. 45.
Statistical publications
Online databases
Indicator in PDF Acrobat PDF page

Overweight and obese population aged 15 and above
    Table in Excel

Obese population aged 15 and above Figure in Excel
Obese population aged 15 and

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