Overweight and obesity

Web report

Last updated: 17 Jun 2024

AIHW

Australian Institute of Health and Welfare (2024) Overweight and obesity, AIHW, Australian Government, accessed 15 September 2024.

APA

Australian Institute of Health and Welfare. (2024). Overweight and obesity. Retrieved from https://www.aihw.gov.au/reports/overweight-obesity/overweight-and-obesity

MLA

Overweight and obesity. Australian Institute of Health and Welfare, 17 June 2024, https://www.aihw.gov.au/reports/overweight-obesity/overweight-and-obesity

Vancouver

Australian Institute of Health and Welfare. Overweight and obesity [Internet]. Canberra: Australian Institute of Health and Welfare, 2024 [cited 2024 Sep. 15]. Available from: https://www.aihw.gov.au/reports/overweight-obesity/overweight-and-obesity

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Australian Institute of Health and Welfare (AIHW) 2024, Overweight and obesity, viewed 15 September 2024, https://www.aihw.gov.au/reports/overweight-obesity/overweight-and-obesity

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Measuring overweight and obesity

Body Mass Index

Body Mass Index (BMI) is an internationally recognised standard for classifying overweight and obesity in adults. BMI is calculated by dividing a person’s weight in kilograms by the square of their height in metres.

BMI does not necessarily reflect body fat distribution or describe the same degree of fatness in different individuals. However, at a population level, BMI is a practical and useful measure for identifying overweight or obesity. Figure 1 can be used to calculate your BMI.

Figure 1: BMI calculator and distribution, persons aged 18 and over, by sex, 2022

Table 1: BMI classification in adults
BMI (kg/m²)	Classification
Less than 18.5	Underweight
18.5 to less than 25	Normal weight
25 or more	Overweight or obese
25 to less than 30	Overweight but not obese
30 or more	Obese
30 to less than 35	Obese class I
35 to less than 40	Obese class II
40 or more	Obese class III

Source: WHO 2000.

Height and body composition are continually changing for children and adolescents as they grow. Different BMI cut-off points based on age and sex are used when assessing their BMI at a population level (Cole, et al. 2000).

Waist circumference

Waist circumference is an alternative way to assess the risk of developing obesity-related chronic diseases. A higher waist measurement is associated with an increased risk of chronic disease. The threshold at which waist circumference indicates an increased risk of developing disease are dependent on gender and ethnicity (NHMRC 2013). The threshold may also be less accurate in some situations such as pregnancy and medical conditions where there is distension of the abdomen (Heart and Foundation 2023). The risk levels presented below are for Caucasian men and women.

Table 2: Waist circumference associated with increased risk of metabolic complications
Sex	Increased risk	Substantially increased risk
men	94cm	102cm
women	80cm	88cm

Source: NHMRC 2013.

For information on how to correctly measure your waist, visit the National Heart Foundation website,

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