Australian Institute of Health and Welfare (2021) Body mass index, AIHW, Australian Government, accessed 29 January 2023.
Australian Institute of Health and Welfare. (2021). Body mass index. Retrieved from https://www.aihw.gov.au/reports/children-youth/body-mass-index
Body mass index. Australian Institute of Health and Welfare, 25 June 2021, https://www.aihw.gov.au/reports/children-youth/body-mass-index
Australian Institute of Health and Welfare. Body mass index [Internet]. Canberra: Australian Institute of Health and Welfare, 2021 [cited 2023 Jan. 29]. Available from: https://www.aihw.gov.au/reports/children-youth/body-mass-index
Australian Institute of Health and Welfare (AIHW) 2021, Body mass index, viewed 29 January 2023, https://www.aihw.gov.au/reports/children-youth/body-mass-index
Get citations as an Endnote file:
On this page:
A healthy body weight is important for young people’s current and future health. Being either underweight (due to under-nutrition, leading to deficiencies in calories, vitamins and minerals, and proteins) or overweight or obese (where an abnormal or excessive amount of fat accumulates in the body) increases a young person’s risk of poor physical health. Both are risk factors for future illness.
People who are very underweight are at higher risk of having osteoporosis, decreased muscle strength, hypothermia and lowered immunity (DoH 2014).
People who are overweight or obese face an increased risk of developing chronic conditions (such as type 2 diabetes and cardiovascular disease) at younger ages, and some cancers at an earlier age (Llewellyn et al. 2016; Sahoo et al. 2015; VicHealth 2014). Young people with overweight and obesity are more likely to become or remain obese as adults.
Overweight and obesity generally results from a sustained energy imbalance, where the amount of energy consumed through eating and drinking outweighs the energy expended through physical activity and bodily functions (AIHW 2017; WHO 2002). It is influenced by a complex interplay of individual, family, community and societal factors (AIHW 2017, 2020):
In 2015, 8.4% of the disease burden in Australia was due to overweight and obesity; it was the second leading risk factor contributing to disease burden after tobacco use (AIHW 2019). Early intervention in childhood and adolescence is critical for preventing overweight and obesity in the population, as highlighted in the National Action Plan for the Health of Children and Young People 2020–2030 (DoH 2019).
Under Australia’s Long Term National Health Plan, the Australian Government is developing the National Preventive Health Strategy. The aim of the Strategy is to help Australians improve their health at all stages of life, through early intervention, better information, and by targeting risk factors and the broader causes of health and wellbeing (DoH 2020a). The Strategy, to be launched in 2021, will also build on other strategic work – including the National Obesity Strategy (a 10-year framework for action to reduce overweight and obesity) – to be considered by Health Ministers in 2021 (DoH 2020b).
Data from the ABS National Nutrition Survey 1995, the National Health Survey, 2007–08, the Australian Health Survey 2011–12, and the National Health Surveys 2014–15 and 2017–18 are reported here. These surveys collected physical measurements of the height and weight of young people, excluding those living in Very remote areas.
Body mass index (BMI) is used to measure overweight and obesity. It is calculated as the ratio of weight in kilograms divided by height in metres squared (kg/m2). The measurement does not necessarily reflect body fat distribution or degree of fatness among different individuals but is a practical and useful measure for identifying overweight and obesity at a population level.
For children and adolescents (up to the age of 17), age and sex are taken into account when assessing their BMI to account for changes in their body composition as they grow. International cut-off points, based on age and sex, are used when assessing their BMI at a population level (Cole et al. 2000; Cole et al. 2007). The cut-off points used to classify adults aged 18 and over as overweight or obese are as defined by the World Health Organization (WHO 2000).
For more information on measuring overweight and obesity of children and adolescents, see Technical notes below and Appendix A: Defining and measuring overweight and obesity in Overweight and obesity among Australian children and adolescents.
In this section, child and adolescent cut-offs have been used for the 15–17 year age group, and adult cut-offs for 18–24 year olds (see Technical notes).
In 2017–18, among 15–17 year olds, an estimated:
Among 18–24 year olds, an estimated:
Note that proportions and/or estimates of components do not sum due to random adjustment to avoid the release of confidential data.
Source: ABS 2019.
In 2017–18, among 15–17 year olds, the proportion of males and females who were either overweight or obese was similar (30% and 24%, respectively) (Figure 2).
Among 18–24 year olds, the proportion of:
Note: Proportions have been randomly adjusted to avoid the release of confidential data.
The proportion of young people aged 15–17 and 18–24 who are overweight or obese has increased over time.
A comparison of data from 1995 and 2007–08 found that the proportion of 15–17 year olds who were:
Among females, the proportion who were:
Among males, the proportion who were obese was higher in 2007–08 than in 1995 (15% compared with 5.9%); however, results should be treated with caution as the relative standard error (RSE) was high (see Technical notes).
Results for 2007–08 and 2017–18 were similar for all 15–17 year olds, and across both sexes.
Sources: ABS 2009a, 2013b, 2013c, 2016, 2019a.
A comparison of data from 1995 and 2007–08 found that the proportion of 18–24 year olds who were:
Among females aged 18–24, the proportion who were:
Comparing results for 2007–08 and 2017–18, the proportion of 18–24 year olds who were:
Among males aged 18–24, the proportion who were:
It should be noted that different methodologies regarding respondents’ measurements of height and weight were applied for different iterations of the National Health Survey, which may have affected results (see Technical notes for more information).
Sources: ABS 2009b, 2013a, 2015, 2019a.
In 2017–18, among young people aged 15–24:
Based on available data for the 5–19 age group for 41 Organisation for Economic Co-operation and Development (OECD) and European Union countries, in 2016, Australia was among the 10 countries with the highest proportions (34% or more) of children and adolescents who were overweight or obese. While in Australia, the proportion was 34%, the highest proportions were in the United States (42%) and New Zealand (39%), while Greece, Malta and Italy all had 37%. Canada (32%), United Kingdom and Ireland (each 31%) had slightly lower proportions than Australia.
Lower rates tend to be found mostly in countries in northern Europe and East Asia. Japan (14%), Estonia (20%), Lithuania and Latvia (each 21%) had among the lowest proportions (UNICEF Innocenti 2020).
For information on topics related to overweight and obesity of Australia’s youth, see:
For more information on Indigenous young people and BMI, see:
For information on children and BMI, see:
ABS (Australian Bureau of Statistics) 2009a. Microdata: National Health Survey, 2007–08. Findings based on detailed microdata analysis. Canberra: ABS. Viewed 15 March 2021.
ABS 2009b. National Health Survey: summary of results, 2007–2008 (reissue). ABS cat. no. 4364.0. Canberra: ABS. Viewed 19 April 2021.
ABS 2013a. Australian Health Survey: updated results, 2011–12. ABS cat. no. 4364.0.55.003. Canberra: ABS. Viewed 19 April 2021.
ABS 2013b. Microdata: Australian Health Survey, National Health Survey, 2011–12. Findings based on detailed microdata analysis. Canberra: ABS. Viewed 15 March 2021.
ABS 2013c. Microdata: National Nutrition Survey, 1995. Findings based on basic microdata analysis. Canberra: ABS. Viewed 15 March 2021.
ABS 2015. National Health Survey: first results 2014–15. ABS cat. no. 4364.0.55.001. Canberra: ABS. Viewed 19 April 2021.
ABS 2016. Microdata: National Health Survey, 2014–15. ABS cat. no. 4324.0.55.001. Findings based on detailed microdata analysis. Canberra: ABS. Viewed 15 March 2021.
ABS 2019. National Health Survey, 2017–18. Customised report. Canberra: ABS.
AIHW (Australian Institute of Health and Welfare) 2017. A picture of overweight and obesity in Australia 2017. Cat. no. PHE 216. Canberra: AIHW. Viewed 19 April 2021.
AIHW 2019. Australian Burden of Disease Study: impact and causes of illness and death in Australia 2015. Australian Burden of Disease Study series no. 19. Cat. no. BOD 22. Canberra: AIHW. Viewed 19 April 2021.
Cole TJ, Bellizzi MC, Flegal KM & Dietz WH 2000. Establishing a standard definition for child overweight and obesity worldwide: international survey. BMJ 320:1240–3. Viewed 19 April 2021.
Cole TJ, Flegal KM, Nicholls D & Jackson AA 2007. Body mass index cut offs to define thinness in children and adolescents: international survey. BMJ 335(7612):194. Viewed 19 April 2021.
DoH (Department of Health) 2014. For people who are underweight. DoH website. Canberra: DoH. Viewed 11 June 2020.
DoH 2019. National Action Plan for the Health of Children and Young People 2020–2030. DoH website. Canberra: DoH. Viewed 19 April 2021.
Llewellyn A, Simmonds M, Owen CG & Woolacott N 2016. Childhood obesity as a predictor of morbidity in adulthood: a systematic review and meta-analysis. Obesity Reviews 17:56–67. Viewed 19 April 2021.
NHMRC (National Health and Medical Research Council) 2013. Clinical practice guidelines for the management of overweight and obesity in adults, adolescents and children in Australia. Melbourne: NHMRC. Viewed 19 April 2021.
Pont SH, Puhl R, Cook SR & Slusser W 2017. Stigma Experienced by Children and Adolescents With Obesity. Pediatrics 140 (6): e20173034. Viewed 19 April 2021.
Sahoo K, Sahoo B, Choudhury AK, Sofi NY, Kumar R & Bhadoria AS 2015. Childhood obesity: causes and consequences. Journal of Family Medicine and Primary Care 4:187–92. Viewed 19 April 2021.
Sanders RH, Han A, Baker JS & Cobley S 2015. Childhood obesity and its physical and psychological co-morbidities: a systematic review of Australian children and adolescents. European Journal of Pediatrics 174(6):715–46. Viewed 19 April 2021.
Steinbeck K, Lister NB, Gow ML & Baur LA 2018. Treatment of adolescent obesity. Nature Reviews Endocrinology 14(6):331–44. doi: 10.1038/s41574-018-0002-8. Viewed 12 March 2021. Viewed 19 April 2021.
UNICEF Innocenti 2020. Worlds of influence: understanding what shapes child well-being in rich countries. Innocenti report card 16. Florence: UNICEF Office of Research Innocenti. Viewed 19 April 2021.
Van Geel M, Vedder P & Tanilon J 2014. Are overweight and obese youths more often bullied by their peers? A meta-analysis on the relation between weight status and bullying. International Journal of Obesity 38:1,263–67. Viewed 19 April 2021.
VicHealth 2014. Negative growth: the future of obesity in Australia. Research highlights. Melbourne: Victorian Health Promotion Foundation. Publication number: P-HE-142. Viewed 19 April 2021.
WHO (World Health Organization) 2000. Obesity: preventing and managing the global epidemic. Report of a WHO consultation. World Health Organization Technical Report Series 894. Geneva: WHO. Viewed 19 April 2021.
WHO (World Health Organisation) 2002. The world health report 2002 – Reducing Risks, Promoting Healthy Life – Chapter 4. Viewed 12 June 2020.
Body Mass Index is derived from measured height and weight. In 2017–18, 43.9% of respondents aged 2–17 years and 33.8% of respondents aged 18 years and over did not have their height, weight or both measured. For these respondents, imputation was used to obtain height, weight and BMI scores. For more information see National Health Survey: First Results methodology, Appendix 2 – physical measurements.
In 2014–15, 37.7% of respondents aged 2–17 years and 26.8% of respondents aged 18 years and over did not have their height, weight or both measured. For these respondents, imputation was used to obtain height, weight and BMI scores. For more information see Appendix 2 – physical measurements in the National Health Survey, 2014–15.
For 1995 and 2007–08 data excludes 'not measured' and 'not known'.
For 2011–12 data excludes 'measurement not taken - refusal' and 'measurement not taken - other reason'.
For general technical notes relating to this report, see also Methods.
Return to Australia's youth:
We'd love to know any feedback that you have about the AIHW website, its contents or reports.
The browser you are using to browse this website is outdated and some features may not display properly or be accessible to you. Please use a more recent browser for the best user experience.