Overweight and obesity

Obesity is defined as having a body mass index (BMI) equal to or greater than 30.

The latest data from the National Health Survey 2017–18 suggests that almost a third of Australian and Victorian adults are obese (Australian Bureau of Statistics 2018).

Another third of adults are overweight, with a BMI between 25 and 30 (Australian Bureau of Statistics 2018).

By these estimates, 68 per cent (over two-thirds) of Victorian adults are overweight or obese, which is an estimated 3.3 million people (Australian Bureau of Statistics 2018), see Table 1.

Table 1: Proportion of adults (aged 18 and over) overweight and obese, Australian Bureau of Statistics 2018

Data are age-standardised

In addition, nearly a quarter of our children are also overweight or obese (Australian Bureau of Statistics 2018).

This is a concerning trend, as obese children and adolescents are five times more likely to be obese in adulthood than those who are not obese, with 80 per cent of obese adolescents going on to be obese in adulthood (Simmonds, et al. 2016).

Burden of disease

Overweight and obesity has become the second-leading modifiable cause of the disease burden in Australia, responsible for 8.4 per cent of the total disease burden and 19.3 per cent of the cardiovascular burden (Australian Institute of Health and Welfare 2019).

Overweight and obesity are among the greatest risk factors driving death and disability in Australia.

They are significant risk factors for hypertension, cardiovascular disease, type 2 diabetes, gallbladder disease, musculoskeletal disorders, some cancers (endometrial, breast and bowel), psychological disorders and breathing difficulties (World Health Organization 2013).

Ultimately, being obese can lead to disability and premature death (Department of Health and Human Services 2018).

Victorian data indicates that factors such as presence of psychological distress, doctor-diagnosed hypertension and self-reported fair or poor health are positively associated with being overweight (Department of Health and Human Services 2018).

The national context

More than 21,000 people are surveyed nationally by the Australian Bureau of Statistics, with body mass index measured for two-thirds of respondents.

For the remaining third, height and weight were imputed using a range of information, including their self-reported height and weight.

This puts Australia in the top quarter of Organisation for Economic Cooperation and Development (OECD) countries for measured obesity, ahead of the United Kingdom (26.2 per cent of the population) and Ireland (23 per cent), on a par with New Zealand (31.6 per cent), but behind the United States of America (40 per cent).

In the last decade, two things have occurred:

• more people are overweight and obese (68 per cent of the population compared to 61 per cent in 2007–08)
• and the proportion who are obese has increased to 32 per cent of the population from 25 per cent in 2007–08.

The changes in body mass of Victorians mirror Australian data.

The obesity rate has been trending up in the last decade and in 2017–18 surpassed 30 per cent for the first time.

Table 2: Proportion of adult population obese

Over the last two decades, the average Australian man and woman has gained 5 kilograms in weight.

In 2017–18 the average Australian man weighed 87 kilograms compared with 82 kilograms in 1995.

The average Australian woman weighed 72 kilograms compared with 67 kilograms in 1995.

Figure 1: Sex distribution of body mass index, Victoria 2017–18

Source: Department of Health and Human Services

Figure 1 shows that around three-quarters of Victorian males are overweight and obese compared to 60 per cent of females.

Fewer than a quarter of males are now in the normal weight range. This difference between males and females is due to a lower proportion of females being overweight, but the proportion of females who are obese is almost the same as for males.

Figure 2 shows the proportion of the Victorian population overweight or obese by age. A quarter of children aged 2–17 years are overweight or obese.

This age group is already overweight or obese by the time they start school. The rate then stays around this level through the school years with small fluctuations, before accelerating sharply during the late teen/young adulthood period.

Figure 2: Proportion of population overweight or obese by age group, Victoria

Source: Department of Health and Human Services

Data averaged over last three surveys (2011–12, 2014–15, 2017–18) to minimise fluctuations due to the small sample sizes per age group.

What the Victorian Government is doing

In addition to measures to support healthy eating the Victorian Government through VicHealth also funds programs and initiatives that contribute to obesity prevention.

References

Australian Bureau of Statistics 2018, National health survey 2017–18, Australian Bureau of Statistics, Canberra.

Australian Institute of Health and Welfare 2019, Australian burden of disease study: impact and causes of illness and death in Australia 2015, Australian Institute of Health and Welfare, Canberra.

Department of Health and Human Services 2018, Victorian population health survey 2016. Melbourne: Victorian Government.

Simmonds M, Llewellyn A, Owen C and Woolacott N, 2016, 'Predicting adult obesity from childhood obesity: a systematic review and meta-analysis', Obesity Reviews, vol. 174, no. 2.

World Health Organization 2013, Overweight and obesity fact sheet number 311, World Health Organization, Geneva.