Obesity

March 2012

Key facts

  • Overweight and obesity are defined as Body Mass Index (BMI), a measure of weight relative to height, with overweight expressed as BMI ≥ 25 and obesity as BMI ≥ 30.
  • Overweight and obesity, are increasing globally as a result of dietary changes and decreasing physical activity.
  • The risk of hypertension, coronary heart disease, stroke and type 2 diabetes grows progressively with increasing body mass index, as do the risks of cancers of the breast, colon, prostate, endometrium, kidney, gall bladder and other organs. Chronic overweight also contributes to osteoarthritis—a major cause of disability in later life.
  • Globally, 44% of diabetes, 23% of ischaemic heart disease and between 7% and 41% of certain cancer burdens are attributable to overweight and obesity.
  • WHO estimates that more than 1 billion people worldwide are overweight and more than 300 million are obese and that at least 2.8 million people die each year as a result of being overweight or obese.
  • The worldwide prevalence of obesity just about doubled between 1980 and 2008. In 2008, 10% of men and 14% of women in the world were obese, compared with 5% for men and 8% for women in 1980.
  • Rates of overweight and obesity are projected to increase in almost all countries reaching 1.5 billion people who are overweight by 2015.
  • To achieve optimum health, the goal should be a body mass index in the range 18.5 to 24.9 kg/m2.

Global comparisons

  • The prevalence of overweight and obesity are highest in the WHO Regions of the Americas (62% for overweight in both sexes, and 26% for obesity) and lowest in the WHO Region for South-East Asia (14% overweight in both sexes and 3% for obesity).
  • In the WHO Region for Europe, the WHO Region for the Eastern Mediterranean and the WHO Region for the Americas, over 50% of women are overweight.
  • For all three of these regions, roughly half of overweight women are obese (23% in Europe, 24% in the Eastern Mediterranean, 29% in the Americas).
  • In the Western Pacific Region obesity prevalence is highest in the Pacific Island countries and areas, where some of the highest rates of overweight and diabetes are found, and rapidly increasing in the Asian countries.
  • In all WHO regions, women are more likely to be obese than men.
  • In the WHO regions for Africa, Eastern Mediterranean and South-East Asia, women have roughly double the obesity prevalence of men.
  • Globally, body mass index increases with income, from low-income countries to upper-middle-income countries.
  • The prevalence of overweight in high-income and upper-middle-income countries is more than double that of low- and lower-middle-income countries.
  • The prevalence of obesity is 7% for both sexes combined, in lower-middle-income countries and 24% - more than 3 times greater, in upper-middle-income countries.
  • Women's obesity is significantly higher than men's, with the exception of high-income countries, where it is similar. In low- and lower-middle-income countries, obesity among women is approximately double that among men.
  • Childhood obesity is one of the most serious public health challenges of the 21st century. The problem is global and is steadily affecting many low- and middle-income countries, particularly in urban settings.
  • Prevalence of childhood obesity has increased at an alarming rate. In 2010, an estimated 43 million children under the age of five years were overweight throughout the world. More than 75% of overweight and obese children live in low and middle-income countries.

Key areas for action

  • Curbing the obesity epidemic requires sustained political commitment and the collaboration of many public and private stakeholders.
  • Some recommended steps:
    • Review existing policies to ensure that they are consistent with best practice in promoting healthy diets and increasing physical activity;
    • Develop, promote and support the implementation of national dietary guidelines and guidelines on physical activity for health;
    • Develop national policy for the promotion of physical activity, targeting change in a number of sectors, including fiscal policies to increase access to recreational physical activity, particularly among poor communities;
    • Review urban planning and environmental policies (national and local levels) to ensure a safe and enabling environment for physical activity (e.g. provision of parks, playgrounds and cycle lanes);
    • Ensure transport policies include support for active, non-motorized modes of transport;
    • Review labor and workplace policies to ensure they support physical activity in and around the workplace;
    • Explore fiscal policy that may support participation in physical activity
    • Introduce legislation to support healthier composition of foods;
    • Promote and implement the use of nutrition labeling with simple codes to encourage healthy food choices (e.g. traffic light systems and other culturally appropriate approaches);
    • Develop fiscal policies to encourage consumption of healthier food products, particularly among poor communities;
    • Support pricing strategies with point-of-decision prompts.

Childhood obesity

  • Overweight and obese children are likely to stay overweight into adulthood and more likely to develop noncommunicable diseases such as diabetes and cardiovascular diseases at a younger age than average.
  • Prevention of childhood obesity should therefore be assigned high priority:
  • Some recommended steps:
    • Promote and support six months of exclusive breastfeeding of newborns and the implementation of the Code of marketing of breastmilk substitutes;
    • Promote appropriate complementary feeding practices;
    • Create a healthy school environment and a supporting and enabling environment of the community where the school is located;
    • Ensure school policies support the provision of opportunities and programmes for promoting healthy dietary practices and physical education and activity (consider staff as well as children);
    • Introduce a mass-media campaign targeting primarily parents and care-givers, as well as secondary schoolchildren and adolescents;
    • Reduce marketing of food and non-alcoholic beverages to children.
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