Overweight and obesity is an Australia's health topic

Overweight and obesity refer to excess body weight, which is a risk factor for many diseases and chronic conditions and is associated with higher rates of death. It mainly occurs because of an imbalance between energy intake (from the diet) and energy expenditure (through physical activities and bodily functions).

Genetic factors, schools, workplaces, homes and neighbourhoods, the media, availability of convenience foods, and portion sizes can all influence a person’s body weight.

Measuring overweight and obesity

Body Mass Index (BMI)

  • BMI is an internationally recognised standard for classifying overweight and obesity in adults.
  • While BMI does not necessarily reflect body fat distribution or describe the same degree of fatness in different individuals, at a population level BMI, is a practical and useful measure for monitoring overweight and obesity.
  • BMI is calculated by dividing a person’s weight in kilograms by the square of their height in metres. A BMI of 25.0–29.9 is classified as overweight but not obese, while a BMI of 30.0 or over is classified as obese. A BMI of greater than 35.0 is classified as severely obese.
  • To calculate your BMI and see how it compares with other Australian adults, enter your height and weight into the AIHW BMI calculator.
  • Height and body composition are continually changing for children and adolescents, so a separate classification of overweight and obesity (based on age and sex) is used for people aged under 18 (Cole et al. 2000).

Waist circumference

  • Waist circumference for adults is a good indicator of total body fat and is a better predictor of certain chronic conditions than BMI, such as cardiovascular risk and type 2 diabetes (NHMRC 2013). A waist circumference above 80 cm for women and above 94 cm for men is associated with an increased risk of chronic conditions. A waist circumference above 88 cm for women and above 102 cm for men is associated with a substantially increased risk of chronic conditions (WHO 2000). For information on measuring and understanding your waist circumference, see Heart Foundation.

How common is overweight and obesity?

Children and adolescents

In 2017–18, 1 in 4 (25%) children and adolescents aged 2–17 were overweight or obese (an estimated 1.2 million children and adolescents). Of all children and adolescents aged 2–17, 17% were overweight but not obese, and 8.2% were obese. Rates varied across age groups, but were similar for males and females (ABS 2018a).

Adults

In 2017–18, 2 in 3 (67%) Australians aged 18 and over were overweight or obese (36% were overweight but not obese, and 31% were obese). That’s around 12.5 million adults.

Men had higher rates of overweight and obesity than women (75% of men and 60% of women), and higher rates of obesity (33% of men and 30% of women).

Obesity is more common in older age groups – 16% of adults aged 18–24 were obese, compared with 41% of adults aged 65–74.

See Overweight and obesity: an interactive insight for information on age differences in overweight and obesity.

The proportion of adults with a waist circumference associated with a substantially increased risk of chronic conditions was higher in women than men (46% of women and 36% of men). This risk increased with age (peaking at 57% of men aged 65–74, and 65% of women aged 75–84) (ABS 2018a).

Trends in overweight and obesity

Why is the most recent data from 2017–18?

Nationally representative estimates on measured overweight and obesity are derived from the Australian Bureau of Statistics (ABS) National Health Survey (NHS).

Due to the COVID-19 pandemic, physical measurements (including height, weight and waist circumference) were not taken at the time of the NHS 2020–21, the most recent NHS.

While self-reported height and weight were collected as part of the survey, self-reported data underestimates actual levels of overweight or obesity based on objective measurements (ABS 2018b). 

As self-reported and measured rates of overweight and obesity should not be directly compared, the figures presented on this page reflect the latest nationally representative data based on measured height, weight and waist circumference.   

Children and adolescents

The prevalence of overweight and obesity in children and adolescents aged 5–17 rose from 20% in 1995 to 25% in 2007–08, then remained relatively stable to 2017–18 (25%) (Figure 1).

Similarly, the prevalence of obesity increased from 4.9% in 1995 to 7.5% in 2007–08 then remained relatively stable to 2017–18 (8.1%). Rates of overweight but not obese children and adolescents increased between 1995 and 2014–15 (from 15% to 20%), then declined to 17% in 2017–18 (ABS 2013a, 2015, 2019; AIHW analysis of ABS 2009, 2013b).

See Overweight and obesity among Australian children and adolescents for more information.
 

This graph shows the prevalence over time of overweight and obesity in children and adolescents. Three lines indicate the proportions for total overweight or obese, overweight but not obese, and obese across 5 time points (1995, 2007–08, 2011–12, 2014–15 and 2017–18). The graph shows an increase in overweight and obesity from 1995 (20%) to 2007–08 (25%), followed by a stabilisation to 2017–18 (25%).

Adults

After adjusting for different population age structures over time, the prevalence of overweight and obesity among Australians aged 18 and over increased from 57% in 1995 to 67% in 2017–18. This was largely due to an increase in obesity rates, from almost 1 in 5 (19%) in 1995 to just under 1 in 3 (31%) in 2017–18.

The distribution of BMI in adults shifted towards higher BMIs from 1995 to 2017–18, due to an increase in obesity in the population over time (Figure 2).
 

This graph shows the changing distribution of BMI over time in adults aged 18 and over. It shows a shift to the right in BMI distribution between 1995 and 2017–18. In 1995, more adults had a BMI in the normal or overweight range compared with adults in 2017–18. However, in 2017–18, more adults were in the obese weight range compared with adults in 1995.

Health impact

Burden of disease refers to the quantified impact of living with and dying prematurely from a disease or injury.

In 2018, 8.4% of the total burden of disease in Australia was due to overweight and obesity. Overweight and obesity was the leading risk factor contributing to non-fatal burden (living with disease), and the second leading risk factor for total burden, behind tobacco use (AIHW 2021). See Burden of disease.

Overweight and obesity increases the likelihood of developing many chronic conditions, such as cardiovascular disease, asthma, back problems, chronic kidney disease, dementia, diabetes, and some cancers (AIHW 2017). It is also associated with a higher death rate when looking at all causes of death (The Global BMI Mortality Collaboration 2016).

Variation between population groups

See Determinants of health for Indigenous Australians for information on overweight and obesity among Aboriginal and Torres Strait Islander people.

Remoteness area

Overweight and obesity rates differ across remoteness areas, with the lowest rates in Major cities.

In 2017–18, a higher proportion of Australian children and adolescents aged 2–17 living in Inner regional areas were overweight or obese, compared with those living in Major cities (29% and 23% respectively). For children and adolescents living in Outer regional and remote areas, the proportion was 27% (ABS 2019).

For Australians aged 18 and over, after adjusting for age differences, 70% of adults living in Outer regional and remote areas and 71% in Inner regional areas were overweight or obese, compared with 65% in Major cities (Figure 3). See Rural and remote health.

Socioeconomic area

Overweight and obesity rates differ across socioeconomic areas, with the highest rates in the lowest socioeconomic areas.

In 2017–18, obesity rates for children and adolescents aged 2–17 were 2.4 times as high in the lowest socioeconomic areas (11%) compared with the highest socioeconomic areas (4.4%). For overweight and obesity combined, rates were also higher in the lowest socioeconomic areas (28%) compared with the highest socioeconomic areas (21%) (ABS 2019).

In 2017–18, Australians aged 18 and over, after adjusting for age differences, in the lowest socioeconomic areas were more likely to be overweight or obese than those in the highest socioeconomic areas: 72% compared with 62%. Obesity rates were the underlying reason for this difference (38% compared with 24% respectively) (Figure 3). See Health across socioeconomic groups.
 

This graph shows that the prevalence of overweight or obesity was higher for those living in Inner regional (71%), and Outer regional and remote (70%) areas, than for those living in Major cities (65%). It also shows the prevalence of overweight or obesity increased as disadvantage increased—from 62% for quintile 5 (highest socioeconomic areas) to 72% for quintile 1 (the lowest socioeconomic areas).

Visualisation not available for printing

Impacts of COVID-19 on overweight and obesity

The data presented are the latest national statistics available on measured overweight and obesity, based on the ABS NHS.

Nationally representative data on people’s weight in Australia during COVID-19 are not currently available. However, emerging research suggests that COVID-19 might have had an impact on the weight of some Australians.

Data from SiSU health check stations across Australia have shown that non-seasonal spikes in measured BMI was evident in their users from March 2020, coinciding with the period that public health restrictions due to COVID-19 were starting to take place (SiSU Health 2020). However, it should be noted that users of SiSU health check stations tend to be younger, female and more socioeconomically advantaged than the general Australian population (Flitcroft et al. 2020).

For more information on how the pandemic has affected the population's health in the context of longer-term trends, please see ‘Chapter 2 Changes in the health of Australians during the COVID-19 period' in Australia's health 2022: data insights.

Where do I go for more information?

For more information on overweight and obesity, see:

Visit Overweight & obesity for more on this topic.