Overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health. Body mass index (BMI) is a simple index of weight-for-height that is commonly used to classify overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m2).
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. 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 children, age needs to be considered when defining overweight and obesity. 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.
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. In 2016, more than 1.9 billion adults aged 18 years and older were overweight. Of these over 650 million adults were obese.In2016, 39 per cent of adults aged 18 years and over (39 per cent of men and 40 per cent of women) were overweight.
Overall about 13 per cent of the world’s adult population (11 per cent of men and 15 per cent of women) were obese in 2016. (UNI)