Excess body weight, known as overweight and obesity, is a risk factor for many conditions, including cardiovascular disease, high blood pressure, type 2 diabetes, sleep apnoea and osteoarthritis. Overweight and obesity is among the leading causes of death and disability in Australia (AIHW 2019b).
Body mass index
One way of measuring excess body weight at the population level is to use the body mass index (BMI)—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. Differences in body composition may affect the appropriateness of BMI and different BMI cut-off points may need to be considered for certain population groups such as:
- older people
- people with high muscle mass
- certain ethnic groups, including Aboriginal and Torres Strait Islander, Pacific Islander, South Asian, Chinese and Japanese populations (NHMRC 2013).
Height and body composition are continually changing for children and adolescents. A separate classification of overweight and obesity for children is used based on age and sex (Cole et al. 2000). Information in this section relates to measures of overweight and obesity as estimated using BMI.
3 in 4
Australian men are overweight or obese
According to 2017–18 data (ABS 2018):
- 3 in 4 Australian men (75%) were overweight or obese
- 2 in 5 (42%) were overweight (but not obese)
- 3 in 10 (33%) were obese.
Overweight and obesity is more common in older age groups, around 4 in 5 men aged 55–64 were overweight or obese (84%), compared with 1 in 2 men aged 18–24 (52%) (ABS 2019c).
The proportion of men who were overweight or obese varied for some population groups. After adjusting for age (ABS 2013, ABS 2019c):
- men living in the lowest socioeconomic areas were slightly more likely to be overweight or obese as men living in the highest socioeconomic areas (77% and 73%, respectively)
- in 2012–13, the overall rate of overweight and obesity was the same for Aboriginal and Torres Strait Islander men and non-Indigenous men (70% for both). For obesity alone, 39% of Indigenous men were obese in 2012–13, compared with 27% of non-Indigenous men.
The proportion of males who were overweight or obese in 2017–18 differed between men and boys (ABS 2019c):
- 3 in 4 (75%) men aged 18 and over were overweight or obese
- 1 in 4 (25%) boys aged 2–17 were.
Overweight and obesity among boys aged 2–17 varied for some population groups (ABS 2019c):
- boys living in Inner regional areas were 1.3 times as likely to be overweight or obese as boys in Major cities (30% and 24%, respectively)
- boys living in the second-lowest socioeconomic areas were 1.4 times as likely to be overweight or obese as boys in the highest socioeconomic areas (30% and 21%, respectively)
- boys living in the lowest socioeconomic areas were 3 times as likely to be obese as boys in the highest socioeconomic areas (11% and 3.4%, respectively).
Figure 7: Body mass index, boys aged 2–17 and men aged 18 and over, 2017–18
Note: Totals may not add to 100% due to rounding
Chart: AIHW. Source: ABS 2018 (see Table S5 and Table S6 for footnotes).
For more information see Overweight and obesity.
Waist circumference is another common measure of overweight and obesity. For men, a waist circumference above 94 cm is associated with an increased risk of metabolic complications and a waist circumference above 102cm is associated with substantially increased metabolic risk (WHO 2011).
3 in 5
Australian men have a waist circumference associated with increased or substantially increased metabolic risk
According to 2017–18 data, 3 in 5 (60%) Australian men have a high-risk waist circumference— that is, one associated with an increased or substantially increased risk of metabolic complications (Figure 8). The average waist circumference for men aged 18 in over in 2017–18 was 98cm (ABS 2018).
High-risk waist circumference was more common in older men (ABS 2019a):
- 8 in 10 men aged 65–74 (81%) had a high-risk waist circumference
- 3 in 10 men aged 18–24 did (29%).
The prevalence of high-risk waist circumference varied for some population groups. After adjusting for age (ABS 2019a):
- men living in Outer regional and remote areas were 1.1 times as likely as men in Major cities to have a high-risk waist circumference (61% and 58%, respectively)
- men living in the lowest socioeconomic areas were 1.2 times as likely as men in the highest socioeconomic areas to have a high-risk waist circumference (62% and 53% respectively).
Figure 8: Waist circumference of men, by risk category, 2017-18
Note: Totals may not add to 100% due to rounding.
Chart: AIHW. Source: ABS 2019a (see Table S7 for footnotes).
Management of overweight and obesity
While excess weight is commonly managed using dietary intervention and exercise, for those who are morbidly obese or who are obese and have other conditions related to their excess weight, weight loss surgery may be appropriate.
Weight loss surgery (bariatric surgery) aims to help obese patients lose weight and lower the risk of medical problems associated with obesity. It restricts the amount of food a recipient can eat or alters the process of food digestion so fewer calories are absorbed.
In 2017–18, males accounted for 20% of procedures for weight loss surgery (7,900 procedures). The rate of weight loss surgeries among males for the same year was 64 per 100,000, an increase from 2015–16 with 6,000 procedures and a rate of 50 per 100,000 (AIHW 2019a).
For more information see Weight loss surgery in Australia 2014–15.