Time trends

The interactive graphs below allow you to explore how the prevalence of overweight and obesity has changed over time in different populations, using nationally representative measured height and weight data.

Children and adolescents

National data on overweight and obesity among 5–17 year olds are available from national health surveys conducted by the ABS, dating back to 1995.

The proportion of children and adolescents who were overweight or obese increased between 1995 and 2007–08 (from 20% to 25%), then remained relatively stable from 2007–08 to 2017–18 (ABS 2009b, 2013a, 2013b, 2015, 2019b) (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 rose between 1995 and 2014–15 (from 15% to 20%), then declined to 17% in 2017–18.

This line chart shows 3 separate lines for the proportion of children and adolescents who were overweight or obese, overweight but not obese, and obese in 1995, 2007–08, 2011–12, 2014–15 and 2017–18. Overweight and obesity increased between 1995 and 2007–08 (from 20% to 25%), then remained relatively stable from 2007–08 to 2017–18.

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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. Over this time period, the prevalence of obesity increased substantially, from 1 in 5 (19%) in 1995 to 1 in 3 (31%) in 2017–18. The prevalence of overweight but not obese declined from 38% to 36%.

This line chart shows 3 separate lines for the age-standardised proportion of adults who were overweight or obese, overweight but not obese, and obese in 1995, 2007–08, 2011–12, 2014–15 and 2017–18. The prevalence of overweight and obesity increased from 57% in 1995 to 67% in 2017–18, while the prevalence of obesity increased from 19% to 31% over this period.

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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. 

This chart shows the smoothed distributions of BMI among adults in 1995 and 2017–18, with the BMI cut-off points for underweight, normal weight, overweight and obese also shown on the chart. Compared with 1995, the 2017­–18 distribution has shifted to the right, indicating an increase in obesity over time.

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Birth cohorts

The prevalence of overweight and obesity differs by birth cohort (that is, a group of people born in the same year or years).

A recent AIHW report (AIHW 2020a) compared children, adolescents and young people in 2017–18 with those of the same ages 10 years earlier in 2007–08 and 22 years earlier in 1995. Those born most recently (in 2003–2012) were more likely to be overweight or obese at age 5–14 (24%) than those born in 1981–1990 at the same age (20%). They were also more likely to be obese (7.7% compared with 5.1%). However, the 2003–2012 birth cohort was not significantly more likely to be overweight or obese at age 5–14 than those born in 1993–2002.

For adolescents and young people aged 15–24, those born most recently (in 1993–2002) were more likely to be overweight or obese (41%) than those born in 1983–1992 at the same age (36%) and those born in 1971–1980 at the same age (28%). The 1993–2002 birth cohort was also more likely to be obese at age 15–24 (14%) than those born in 1971–1980 at the same age (8.4%).

When comparing the 1993–2002 birth cohort as they aged from 5–14 to 15–24, the prevalence of overweight and obesity increased with age (from 23% to 41%). Obesity also increased, from 6.4% to 14%.

This bar chart shows the prevalence of overweight and obesity for different birth cohorts at age 5–14 and age 15–24, separately for males and females. It shows that at age 5–14, boys born in 2003–2012 were more likely to be overweight or obese than boys born in 1981–1990 at the same age (25% compared with 19%). At age 15–24, males born in 1993–2002 were more likely to be overweight or obese than males born in 1971–1980 at the same age (46% compared with 32%), as were females (35% of females born in 1993–2002, compared with 24% of females born in 1971–1980). However, only males had a significant increase in overweight and obesity between the 1983–1992 and 1993–2002 cohorts (increasing from 38% to 46%). When comparing the 1993–2002 birth cohort as they aged from 5–14 to 15–24, the prevalence of overweight and obesity increased with age for males (from 24% to 46%) and females (from 22% to 35%).

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In most adult age groups assessed in a recent AIHW report (AIHW 2020b), adults born most recently were significantly more likely to be obese than those born 10 years earlier. The largest absolute difference was at age 75–84, where an additional 11 in every 100 adults were obese at age 75–84 in 2017–18 compared with 2007–08.

Between 1995, 2007–08 and 2017–18, the prevalence of obesity increased significantly for almost all birth cohorts. The largest absolute change in the prevalence of obesity over the 22 years was among the 1973–1982 birth cohort. The prevalence of obesity in this birth cohort nearly tripled from 6.5% when they were aged 13–22 (in 1995) to 19% when they were aged 25–34 (in 2007–08), then increased to 31% when they were aged 35–44 (in 2017–18).

This line chart shows the prevalence of overweight and obesity and obesity for 9 birth cohorts, with data for each cohort shown at the midpoint of the cohort’s age group at up to 3 time points (1995, 2007–08 and 2017–18). For most birth cohorts, the prevalence of overweight and obesity generally increased with age over time, and the group with the highest prevalence is 65–74 year olds in 2017–18 with 40% having obesity and 78% being overweight or obese.

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For more details on these birth cohort analyses, see Overweight and obesity in Australia: an updated birth cohort analysis and Overweight and obesity among Australian children and adolescents.

International comparisons

International comparisons of the prevalence of overweight and obesity can be made for OECD member countries with data available for measured BMI, based on data from 2019 or the latest available year (OECD 2020a).

Australia ranked 5th out of 23 countries with available data for the proportion of people aged 15 and over who are obese (30%)—this was greater than the OECD average of 24%.

Australia ranked 6th out of 22 countries with available data for the proportion of people aged 15 and over who were overweight or obese (65%)—this was greater than the OECD average of 59%.

When comparing the proportion of obese men and women across OECD countries, Australia had the 2nd highest proportion of obese men (32%), behind the United States (38%). The proportion of obese women in Australia was 8th highest out of 23 countries (29%)—higher than the OECD average of 25% for women.

This bar chart shows the proportion of people aged 15 and over who were overweight or obese in OECD countries in 2019 or the nearest year data were available, for males, females and persons. It shows Australia had the 6th highest proportion for overweight and obesity combined (65%), and the 5th highest proportion for obesity (30%). These were higher than the OECD averages of 59% and 24% respectively.

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Australia is among a number of OECD member countries in which the prevalence of overweight and obesity has increased over recent decades, and in Australia as well as most other countries, this increase has been driven by the increased proportion of people who are obese (OECD 2020a). This upward trend is expected to continue—OECD projections show a steady increase in obesity rates until at least 2030 (OECD 2017).

This line chart shows the proportion of people aged 15 and over who were overweight or obese in OECD countries each year from 2000 to 2019 (or the nearest year data were available). It shows that Japan and Korea had much lower rates of overweight and obesity than other countries, with Japan having the lowest prevalence across all years of data (ranging from about 24% to 27%). The country with the highest prevalence of overweight and obesity is Mexico at 75% in 2018.

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For more information, see International health data comparisons, 2020.