Overweight and obesity

Overweight or obesity refers to excess body weight. It is a risk factor for many chronic conditions and is associated with higher rates of death (AIHW 2024a). It is a complex health issue that can have strong impacts on both mental and physical health. At a population level, overweight and obesity is generally measured using Body Mass Index (BMI) or waist circumference.

The root causes of overweight and obesity are varied and complex. The interaction between biological factors (such as genetics) and modern environments that promote unhealthy foods and drinks and sedentary lifestyles, all play a role in influencing energy balance and body weight, and is reported as a reason for the increase in obesity prevalence over the years (Commonwealth of Australia 2022; The Obesity Collective 2026).

Many of the factors that influence energy balance and body weight are outside the control of the individual (Commonwealth of Australia 2022; Department of Health 2021). Social, cultural, physical, political, economic and commercial environments (see What are Determinants of Health), as well as the ability to access resources, all impact a person's likelihood of overweight or obesity (Commonwealth of Australia 2022; Department of Health 2021). To support the health of all Australians, a holistic and system-wide approach is needed, with a focus on addressing the wider determinants of health. For more information, see National strategies for addressing overweight or obesity.

People living with overweight or obesity experience conscious and unconscious weight stigma in many social settings, due to the perception that obesity is a personal responsibility. This disregards the complex nature of overweight and obesity. The co-occurrence of overweight and obesity and eating disorders is also important to acknowledge, as eating disorders are often under-diagnosed and undertreated in people living with overweight and obesity (NEDC 2023).

How common is overweight and obesity?

Based on BMI calculated from measured height and weight data from the ABS 2022–24 NHMS, an estimated (AIHW analysis of ABS 2025b):

• 27% (approximately 1.4 million) of children and adolescents aged 2–17 were living with overweight or obesity – including 8.5% living with obesity
• 67% (approximately 13.2 million) of adults aged 18 and over were living with overweight or obesity – including 33% living with obesity.

More males aged 18 and over (72%) than females (62%) were living with overweight or obesity, driven by higher rates of males (38%) than females (30%) living with overweight (but not obesity).

Based on measured waist circumference data from the ABS 2022–24 NHMS (AIHW analysis of ABS 2025b):

• an estimated 48% of adults aged 18 and over were living with abdominal obesity, indicating a substantially increased risk of developing metabolic complications
• more females (54%) than males (42%) were living with abdominal obesity.

For more information, see How many Australians are living with overweight and obesity?.

Aboriginal and Torres Strait Islander (First Nations) people

Based on measured data from the 2022–23 ABS NATSIHS, an estimated (ABS 2024c):

• 30% (around 102,000) of children and adolescents aged 2–17 were living with overweight or obesity – including 10% living with obesity
• 72% (around 430,000) of adults aged 18 and over were living with overweight or obesity – including 44% living with obesity
• 74% (around 443,500) were living with abdominal overweight or obesity – including 58% living with abdominal obesity.

The proportion of First Nations adults living with overweight or obesity varied by remoteness. More First Nations adults in non-remote areas (73%) were living with overweight or obesity, compared with remote areas (63%).

For more information, see Aboriginal and Torres Strait Islander (First Nations) people.

How does overweight or obesity change over time?

The proportion of Australians living with overweight or obesity has generally increased over time. For children, this is largely driven by increases in the proportion living with overweight, while for adults this is largely driven by the proportion living with obesity.

For children aged 5–17, those living with overweight or obesity increased from 20% in 1995 to 25% in 2017–18, then continued to increase to 28% in 2022–24.

The proportion of adults aged 18 and over living with overweight or obesity remained stable between 2017–18 and 2022–24 (both at 67%), but increased over a longer time period, from 56% in 1995. In particular, adults living with obesity has increased from 19% in 1995 to 33% in 2022–24 (Figure 1).

The proportion of adults aged 18 and over living with abdominal overweight or obesity increased between 2017–18 (63%) and 2022–24 (69%). The prevalence of abdominal overweight or obesity has increased steadily over time, from 45% in 1995. Notably, adults living with abdominal obesity almost doubled from 25% in 1995 to 48% in 2022–24 (Figure 1).

For more information, see Trends over time.

Birth cohort analysis

A birth cohort is a group of people born in the same year, or range of years. Birth cohort analysis can be used to identify groups that are particularly at risk of a health outcome.

Difference between birth cohorts 

Based on AIHW analysis of ABS data, when compared at the same age, Australians born more recently were more likely to be living with overweight or obesity than those born in earlier birth cohorts. 

Results showed that (ABS 2014a, 2025b):

• Almost 10 additional adults in every 100 adults aged 45–54 were living with abdominal obesity (measured by waist circumference) in 2022–24 (55%), compared with those at the same age in 2011–12 (46%).
• An additional 9 in every 100 adults aged 25–34 were living with abdominal obesity (measured by waist circumference) in 2022–24 (36%), compared with those at the same age in 2011–12 (27%).
• Almost 9 additional adults in every 100 adults aged 25–34 were living with obesity (measured by BMI) in 2022–24 (29%), compared with those at the same age in 2011–12 (20%).

Cohort changes over time as they age

Long-term trends between 1995 and 2022-24 showed that the prevalence of obesity and severe obesity (defined by BMI) and abdominal obesity (defined by waist circumference) increased for all 10-year birth cohorts as they aged over time (Figure 2).

When looking at change between 2017–18 and 2022–24, the prevalence of abdominal obesity increased significantly for almost all 5-year birth cohorts as they aged over this period. In contrast, the prevalence of obesity and severe obesity showed no significant increases for those in birth cohorts born before the late 1960s to mid 1970s. For those born after this period, the prevalence of obesity and severe obesity continued to increase (Figure 2).

For more information, see Birth cohort analysis. For more information on the methodology for the birth cohort analysis, see Technical notes. 

How does overweight and obesity vary by priority population group?

Overweight and obesity varied between population groups. Prevalence was, on average, greater among people living in lower socioeconomic (more disadvantaged) areas and people living in remote areas.

Based on measured data from the 2022–24 NHMS (ABS 2025b), of adults aged 18 and over:

• 73% of people in Inner regional and 74% of people in Outer regional and remote areas were living with overweight or obesity, compared with 65% in Major cities. This pattern across remoteness areas was also seen in those living with abdominal obesity.
• 70% of people in the lowest socioeconomic areas (most disadvantaged) were living with overweight or obesity, compared with 62% of those in the highest socioeconomic areas (least disadvantaged).

More children and adolescents aged 2–17 from the lowest socioeconomic areas (36%) were living with overweight or obesity compared with those in the highest socioeconomic areas (22%).

For more information, see How does overweight and obesity rates vary by priority population groups?.

What are the impacts of overweight and obesity?

Burden of disease

Burden of disease measures the impact of living with illness and injury and dying prematurely. A portion of this burden is due to modifiable risk factors.

In 2024, overweight (including obesity) became the leading risk factor contributing to ill health and death, overtaking tobacco use. It was responsible for 8.3% of the total disease burden in Australia (AIHW 2024a). 

About 19,000 deaths (10% of all deaths) in 2024 were attributable to overweight (including obesity). Of these, 6.1% of deaths were attributable to obesity alone – an increase from 5.1% in 2011 (AIHW 2026b). 

For more information, see Burden of disease.

Health expenditure

Health expenditure is money spent on health goods and services. It includes money spent by all levels of governments as well as non-government entities, for example, individuals and private health insurers (AIHW 2025a). 

In 2023–24, of the estimated $180 billion of total health spending on health conditions, $10.8 billion was either attributed to the risk factor overweight (including obesity) or spent on the treatment of obesity (AIHW 2025b, 2025c). Of this amount:

• an estimated $10.1 billion of the expenditure on health conditions was due to overweight (including obesity) – including almost $6 billion of the total spending on type 2 diabetes (57% of spending), chronic kidney disease (46%), coronary heart disease (31%) and osteoarthritis (29%) being attributed to overweight (including obesity).
• almost $800 million was spent on the treatment and management of obesity.

In 2023–24, the pattern of spending on overweight and obesity was different between males and females. Spending on treatment and management of obesity was higher in females (around $570 million) than in males (around $210 million), while spending on treatment for conditions due to overweight (including obesity) was higher in males ($5.5 billion) than in females ($4.5 billion) (AIHW 2025b, 2025c, 2026a). 

For more information, see Health care expenditure related to overweight or obesity.

Hospitalisations

In 2023–24, there were about 27,600 hospitalisations (0.22% of all hospitalisations) with a principal diagnosis of obesity. Of these, 94% had a procedure for obesity, such as bariatric surgery (weight-loss surgery).

There were about 541,000 hospitalisations (4.3% of all hospitalisations) where obesity was recorded as a condition that may impact a patient's episode of clinical care (AIHW 2025e).

For more information, see Hospitalisations related to obesity.

Mortality and deaths

Obesity can be either an underlying or associated cause of death. When obesity is recorded on a death certificate, it is most often reported as a contributory (associated) cause of death (AIHW 2024b). Obesity is likely to be under-represented in mortality data, which may be amplified due to differing certification practices across jurisdictions.

In 2024, around 2,200 deaths involved obesity (AIHW 2026b), which included around:

• 400 deaths with obesity as the underlying cause of death
• 1,800 deaths with obesity as an associated cause of death.

For more information, see Mortality and deaths related to overweight or obesity.

Management and treatment

Managing and treating overweight and obesity involves a holistic approach that is tailored to a person’s individual needs. This may include nutrition, movement, sleep and psychological support, pharmacotherapy or bariatric surgery (weight-loss surgery).

Weight-loss medications for the treatment of overweight and obesity can be used in combination with other treatments, such as lifestyle interventions. Most medications work by either reducing hunger or increasing satiation or both. The use of prescribed medications has increased in recent years. 

Having access to early intervention and supportive health care is crucial for the management and treatment of overweight and obesity. However, in Australia, there are barriers to accessing equitable and effective treatment and management for people living with obesity (Rigas et al. 2023). The high cost of weight-loss medicines is also a barrier to receiving equitable access to these medicines (Forner and Hocking 2025; Marshall 2025). 

For more information, see Management and treatment of overweight and obesity. 

National strategies for addressing overweight and obesity

The root causes of overweight and obesity is complex, with many factors – environmental, social, commercial, political and economic – contributing to its development. 

Preventing overweight and obesity extends far beyond an individual’s responsibility to eat healthier and exercise more. It requires a whole-of-systems approach that tackles all the factors which promote weight gain, as well as creating equity and addressing issues such as weight stigma and discrimination (Department of Health, Disability and Ageing 2022). 

There are 2 national strategies to address overweight and obesity:

• The National Obesity Strategy 2022–2032 is a framework for action to prevent, reduce and treat overweight and obesity in Australia. It focusses on changing current environments which promote weight gain.
• The National Preventive Health Strategy 2021–2030 outlines the long-term approach to prevention in Australia over the next 10 years, with a view to improving the health and wellbeing of Australians through prevention.

Additionally, as the leading risk factor contributing to ill health and death, overweight and obesity is especially relevant to the prevention and management of risk factors and conditions, a focus area of the National Strategic Framework for Chronic Conditions.

The objectives of the National Obesity Strategy and the National Preventive Health Strategy to prevent and address overweight and obesity are supported through national guidelines such as the: 

• 24-hour movement guidelines which provide guidance on how much physical activity Australians should do every day, to achieve optimal health
• dietary guidelines which provide recommendations for eating a variety of nutritious foods from the 5 food groups.

The 2 strategies share the following 2 overweight and obesity targets:

• Halt the rise and reverse the trend in the prevalence of obesity in adults by 2030.
• Reduce overweight or obesity in children and adolescents aged 2–17 years by at least 5% by 2030.

Current assessment of the progress against these targets shows small increasing and stabilising trends in the prevalence of overweight or obesity:

• The proportion of adults aged 18 and over living with obesity was 31% in 2017–18 and 33% in 2022–24. After adjusting for age, this increase was statistically significant (ABS 2019a, AIHW analysis of ABS 2025b).
• The proportion of children and adolescents aged 2–17 living with overweight or obesity has not changed significantly between 2017–18 (25%) and 2022–24 (27%) (ABS 2018c, AIHW analysis of ABS 2025b).

Further monitoring is required to determine whether Australia will meet these targets.

For more information, see National strategies for addressing overweight and obesity and the National preventive health monitoring dashboard.

Where do I go for more information?

For more information, see

• National Preventive Health Strategy 2021–2030
• National Obesity Strategy 2022–2032
• What are determinants of health?
• National preventive health monitoring dashboard
• Inequalities in overweight and obesity and the social determinants of health
• Reducing the burden due to overweight (including obesity) and physical activity

For more on this topic, visit Overweight and obesity.

Helpline and support services

• National Eating Disorders Collaboration
• Butterfly Foundation
• Size Inclusive Health Australia
• InsideOut Institute (Institute for Eating Disorders)
• Eating Disorder Families Australia