The World Health Organization (WHO) has updated its fact sheet on overweight and obesity.
Overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health.
The WHO uses Body Mass Index (BMI) to categorize adults as overweight or obese.
BMI: It is defined as a person’s weight in kilograms divided by the square of his height in meters (kg/m2).
BMI provides the most useful population-level measure of overweight and obesity as it is the same for both sexes and for all ages of adults. However, it should be considered a rough guide because it may not correspond to the same degree of fatness in different individuals.
For adults, WHO defines overweight and obesity as follows:
- overweight is a BMI greater than or equal to 25; and
- obesity is a BMI greater than or equal to 30.
Children between 5 and 19 years of age
Overweight and obesity are defined as follows for children aged between 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.
Children below 5 years’ age
For 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.
In 2014, more than 1.9 billion adults aged 18 years and older were overweight. Of these over 600 million adults were obese.
Overall, about 13% of the world’s adult population (11% of men and 15% of women) were obese in 2014.
In 2014, 39% of adults aged 18 years and over (38% of men and 40% of women) were overweight.
The worldwide prevalence of obesity more than doubled between 1980 and 2014.
Overweight and obesity are linked to more deaths worldwide than underweight.
Globally there are more people who are obese than underweight – this occurs in every region except parts of sub-Saharan Africa and Asia.
Double burden of disease
Many low- and middle-income countries are now facing a “double burden” of disease.
Children in low- and middle-income countries are more vulnerable to inadequate pre-natal, infant, and young child nutrition. At the same time, these 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.
What causes overweight and obesity?
The fundamental cause of obesity and overweight is an energy imbalance between calories consumed and calories expended. Globally, there has been:
- an increased intake of energy-dense foods that are high in fat; and
- an increase in physical inactivity due to the increasingly sedentary nature of many forms of work, changing modes of transportation, and increasing urbanization.
Common health consequences of overweight and obesity
Among adults, raised BMI is a major risk factor for noncommunicable diseases such as:
- cardiovascular diseases (mainly heart disease and stroke), which were the leading cause of death in 2012;
- musculoskeletal disorders (especially osteoarthritis – a highly disabling degenerative disease of the joints);
- some cancers (including endometrial, breast, ovarian, prostate, liver, gallbladder, kidney, and colon).
The risk for these noncommunicable diseases increases, with increases in BMI.
Childhood obesity is associated with a higher chance of obesity, premature death and disability in adulthood. But in addition to increased future risks, obese children experience
- breathing difficulties,
- increased risk of fractures,
- early markers of cardiovascular disease,
- insulin resistance and
- psychological effects.
Reducing overweight and obesity
At the individual level, people can:
- limit energy intake from total fats and sugars;
- increase consumption of fruit and vegetables, as well as legumes, whole grains and nuts; and
- engage in regular physical activity (60 minutes a day for children and 150 minutes spread through the week for adults).
At the societal level
- support individuals in following the recommendations above,
- implement evidence based and population based policies that make regular physical activity and healthier dietary choices available, affordable and easily accessible to everyone, particularly to the poorest individuals.
An example of such a policy is a tax on sugar sweetened beverages.
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.
Link to the updated fact sheet:
Link to the WHO’s page on BMI Global database on BMI):
Link to the WHO BMI for age charts (5-19 years) page:
Link to the WHO child growth standards (weight for height)[0-5 years]: