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Do I have obesity? Weight and health in Australia

What your BMI and waist mean under Australian guidance, why the numbers are lower for Asian, Aboriginal and Torres Strait Islander people, and which health problems they point to.

GLP Guidebook teamUpdated 12 Oct 202610 min read23 sourcesWritten from published sources
The short answer

For most adults in Australia, a BMI of 25 to 29.9 counts as overweight and 30 or more as obesity. For Asian people, and as recommended for Aboriginal and Torres Strait Islander people, the lines are lower: 23 to 27.4 is overweight and 27.5 or more is obesity.1 Your waist matters too: for women, health risk goes up from 80 cm (31.5 in), and for men from 94 cm (37 in).12

Key facts

Overweight
BMI 25 to 29.9, or 23 to 27.4 for Asian, Aboriginal and Torres Strait Islander people1
Obesity
BMI 30 or more, or 27.5 or more for the groups above1
Waist
Risk goes up from 80 cm (31.5 in) for women and 94 cm (37 in) for men, and greatly from 88 cm (34.5 in) and 102 cm (40 in)12
How common
32 in 100 adults live with obesity; 66 in 100 are overweight or living with obesity (measured, 2022)2
What 5–10% loss does
Lowers diabetes risk and improves blood sugar, blood pressure and liver fat3,4,5
What it doesn't decide
Whether you need a medicine. That depends on your whole health, and on a doctor's assessment.1
On this page
  1. What are the Australian cut-offs, and why are some lower?
  2. How do I check my BMI and waist?
  3. When is BMI misleading?
  4. What are "clinical" and "pre-clinical" obesity?
  5. Which health problems are linked to extra weight?
  6. What does losing 5–10% of your weight do?
  7. Is obesity my fault?
  8. Questions people ask

What are the Australian cut-offs, and why are some lower?

Australian doctors use the World Health Organization's BMI bands for most adults, and lower ones for Asian people. The same lower bands are recommended for Aboriginal and Torres Strait Islander people. These groups tend to carry more body fat at the same BMI, so health risk starts lower.1

BMI (body mass index) is your weight compared with your height. The WHO's global cut-offs call a BMI of 25 overweight and 30 obesity.7 In 2004, a WHO expert group found that many Asian people already face high diabetes and heart risk below 25.8 Australia's 2013 national obesity guideline has been rescinded, and a new one wasn't final when we checked.18 The tool most GPs work from is the Australian Obesity Management Algorithm, published in 2024 by the Australian Diabetes Society with obesity, surgical and GP groups (the RACGP).1 Its numbers are below.

What it meansMost adultsAsian people; recommended for Aboriginal and Torres Strait Islander people
Healthy weightBMI 18.5 to 24.97Below 23 (overweight starts at 23)1
OverweightBMI 25 to 29.91BMI 23 to 27.41
ObesityBMI 30 or more1BMI 27.5 or more1
Obesity class 2 and class 3From 35 and from 401From 32.5 and from 37.51
Waist: higher riskWomen from 80 cm (31.5 in), men from 94 cm (37 in); abdominal obesity above 88 cm (34.5 in) and 102 cm (40 in)1,12Women above 80 cm (31.5 in), men above 90 cm (35.5 in)1

The evidence behind it. The algorithm says South Asian, South-East Asian, East Asian, Aboriginal and Torres Strait Islander people have more body fat for a given BMI.1 A study of 1.5 million people in England looked at diabetes risk. South Asian people at a BMI of about 24 had the same risk as white people at a BMI of 30.9 Diabetes Australia says Aboriginal and Torres Strait Islander people are three times more likely to develop type 2 diabetes than non-Indigenous Australians.10 Healthdirect, the government's health information service, adds that BMI is less accurate for Pacific Islander and Māori people too.12

Why websites disagree. Australian guidance uses 27.5 as the obesity line for Asian people, and recommends it for Aboriginal and Torres Strait Islander people.1 Many US and global sites use 30 for everyone.7 Guidelines in India use 25 for people living there.13 They all agree that risk starts earlier for many people. See BMI cut-offs for Asian, Aboriginal and Torres Strait Islander Australians or the India version of this guide.

How do I check my BMI and waist?

Put your numbers in below. You need scales, a tape measure and your height. Nothing you type leaves your device.

I am a
cm
kg
cm

Your BMI and waist check appear here as you type. How to measure your waist

For adults 18 and over. It's a starting point, not a diagnosis: see when BMI is misleading. BMI and waist bands from the Australian Obesity Management Algorithm1 and healthdirect12. Open the full checker (opens in a new tab) for your healthy weight range and a summary to print.

Measuring your waist. Healthdirect suggests this method:12

  • Put the tape directly on your skin, or over light clothing.
  • Measure halfway between your lowest rib and the top of your hip bone. This is usually just above your belly button.
  • Breathe out normally, then read the tape. Keep it snug, but don't squeeze.

The algorithm notes that doctors measure the waist in slightly different places, and the numbers differ a little with each method. What matters most is measuring the same way each time.1

Work it out by hand

BMI is your weight in kg divided by your height in metres, squared.14 Worked example. Sam is a man, 170 cm (5 ft 7 in, or 1.70 m) tall, and weighs 84 kg (185 lb).

  • 1.70 × 1.70 = 2.89
  • 84 ÷ 2.89 = a BMI of about 29.1
  • For most adults, that is overweight. For someone of Asian background, it is in the obesity range, because that line is 27.5.1
  • Sam's waist is 96 cm (38 in). That is above 94 cm, so his risk is raised, though below the 102 cm (40 in) line for abdominal obesity. Using the lower cut-off for Asian men, it is above 90 cm.1,12
What to do with your result. Write down your numbers and take them to your GP. A GP can check whether extra fat is already affecting your body.1,16 The government's free AUSDRISK questionnaire estimates your risk of type 2 diabetes in the next 5 years; you can fill it in yourself or with your GP or practice nurse.11 An HbA1c blood test shows your average blood sugar over the last 2 to 3 months, so ask whether you need one.15 Guide 6 covers seeing a doctor, and our doctor visit checklist (opens in a new tab) helps you prepare.

When is BMI misleading?

BMI can't tell fat from muscle, and it doesn't show where fat sits. So it's a starting point, not a diagnosis.1,16

  • Athletes, body builders and weightlifters can get an "overweight" BMI without much body fat.12
  • People aged over 65: the algorithm says a BMI of 30 doesn't seem to carry the same risk of death in older adults, and there is no clear BMI target at this age. Many also lose muscle and height with age, which BMI can't see.1,17
  • Pregnancy: BMI is less accurate.12
  • People with physical disabilities, and some ethnic groups, including Aboriginal and Torres Strait Islander, Pacific Islander, Māori, South Asian, Chinese and Japanese people: healthdirect says BMI is less accurate for them.12
  • Children and teens under 18: adult cut-offs don't apply. A child's healthy range depends on their age and sex, so use a calculator made for children and teenagers, or ask your GP or child health nurse.12,14
  • A "healthy" BMI with a large waist: the algorithm warns that some people with a BMI in the healthy or overweight range still carry too much fat around the belly, especially older people losing muscle. That is why a waist measure matters too.1

The 2025 Lancet Commission (a panel organised by the medical journal The Lancet Diabetes & Endocrinology) says BMI alone shouldn't be used to judge one person's health. It says to confirm extra fat with a second measure, like waist size.16

What are "clinical" and "pre-clinical" obesity?

They separate extra fat that is already harming your body from extra fat that isn't yet. The question is how your body is working, not just your weight.16

In January 2025, the Lancet Commission, a group of 58 experts, published a new definition. It has been endorsed by 76 organisations.16

  • Pre-clinical obesity: extra body fat, but your organs still work normally. Your risk of future illness is higher.16
  • Clinical obesity: extra fat is already affecting how your body works. Examples include breathlessness, or real limits on daily tasks like bathing or dressing.16
1Measure your BMI and waist
2Is there extra body fat? A high BMI plus a second measure, such as waist-to-height ratio, confirms it.
3Is the extra fat already affecting how your organs work, or limiting daily life?
NoPre-clinical obesityThe Commission advises health advice, regular check-ups and steps to lower the risk of future illness.
YesClinical obesityThe Commission advises timely treatment, chosen with a doctor after a full check-up.

Simplified from the 2025 Lancet Commission.16 This is an international definition. The Australian algorithm still starts from BMI and waist, then looks at weight-related health problems to choose a treatment path.1

These numbers describe your health risk. They don't decide whether you need a medicine. In Australia, medicines approved for weight management have their own rules in their product information: usually from a BMI of 30, or 27 with a weight-related health problem.6 No GLP-1 medicine is subsidised on the PBS (the Pharmaceutical Benefits Scheme) for weight loss.19 Treatment can mean many things, from food and activity changes to medicines or surgery, and the algorithm sets the plan by your BMI, your waist and any weight-related health problems.1 See your options and when a GLP-1 may or may not fit.

Which health problems are linked to extra weight?

Extra body fat, especially around the belly, is linked to type 2 diabetes, heart disease, high blood fats, fatty liver, sleep apnoea, depression, joint pain and some cancers.1,7

The Australian Bureau of Statistics measured adults' height, weight and waist in its 2022 National Health Survey. It found:2

31.7%of adults in Australia living with obesity (2022)2
65.8%overweight or living with obesity (2022)2
67.9%of adults with a waist that raises their risk of disease (2022)2
~1.9MAustralians with diabetes, including up to 500,000 not yet diagnosed10

The conditions, one by one

  • Type 2 diabetes and "prediabetes". An HbA1c blood test shows your average blood sugar over the last 2 to 3 months. Diabetes may be diagnosed at 6.5% (48 mmol/mol) or higher. A result a little lower may mean prediabetes: blood sugar above normal, but not high enough to be diabetes.15
  • High blood pressure and heart disease. The algorithm lists heart disease among the main complications, and high blood pressure among the problems that respond best to weight loss.1
  • Fatty liver (MASLD). This is fat building up in the liver. Its new name is metabolic dysfunction-associated steatotic liver disease.22 It is one of the problems that respond best to weight loss.1,5
  • Sleep apnoea. Breathing stops and starts during sleep. The algorithm asks GPs to screen for it in people with obesity.1
  • Polycystic ovary syndrome (PCOS), a hormone condition that can affect periods and fertility. It is another problem that responds well to weight loss.1
  • Joint pain from wear (osteoarthritis), depression and some cancers.1,7

What does losing 5–10% of your weight do?

For many people, losing 5–10% of body weight brings real health gains. For someone who weighs 90 kg (198 lb), that is about 4.5 to 9 kg (10 to 20 lb).4

These results come from food and activity programmes, not medicines.3,4,5,23

  • Less diabetes. In the US Diabetes Prevention Program, the lifestyle group aimed to lose at least 7% of their weight. Their diabetes rate was 4.8 per 100 people a year, against 11.0 on dummy pills (pills with no medicine in them), a 58% drop.3
  • Every kilo counts. In the same trial, each kg (about 2 lb) lost cut diabetes risk by 16%.21
  • It works in general practice. In the DiRECT trial in Scotland and England, people with type 2 diabetes followed a diet plan led by their GP practice. After a year, 1 in 4 had lost 15 kg (33 lb) or more, and almost half no longer had diabetes. Among those who lost 15 kg or more, 86 in 100 were free of it.20 A similar study in 25 GP practices in New South Wales, DiRECT-Aus, reported that 56 in 100 people were free of diabetes at 12 months.1 DiRECT-Aus had no comparison group, so read it as encouraging, not proof.
  • Better sugar and blood pressure. One study looked at people with type 2 diabetes. Those who lost 5–10% of their weight had about 3.5 times the odds of their HbA1c falling by half a percentage point or more (for example, from 7.5% to 7.0%), compared with people whose weight stayed the same. Blood pressure and blood fats improved too.4
  • Less liver damage. One study followed 293 people with liver inflammation caused by fat. Of those who lost 5% or more, 58% saw it clear. Among those losing 10% or more, 90% did.5

Bigger weight losses generally brought bigger gains in these studies.4,5

Is obesity my fault?

No. Obesity is a long-term medical condition with many causes. It is not a lack of willpower.7,16

The WHO calls obesity a chronic disease, and so does the Australian algorithm.1 It comes from genes, brain signals, eating habits, access to healthy food, marketing and your surroundings.7 The Lancet Commission says blaming individuals isn't supported by the evidence.16

In 2020, experts from many countries signed a joint statement against weight stigma. They found it causes physical and mental harm.23 People who face it are also less likely to get proper care.23

The Australian algorithm tells GPs that weight bias is common in health care and gets in the way of treatment. People who feel judged by their doctor trust them less and avoid appointments. It asks doctors to check their own attitudes.1 The new name for fatty liver also dropped "fatty", which most experts surveyed found stigmatising.22

Questions people ask

My BMI is 28. Do I have obesity?

It depends on your background. For most adults, 28 is overweight. For Asian people, and as recommended for Aboriginal and Torres Strait Islander people, Australian guidance counts 27.5 or more as obesity.1 Check your waist too.12

My BMI is healthy, but my waist is large. Should I worry?

It's worth checking. Some people with a BMI in the healthy or overweight range still carry extra fat around the belly.1 For women, risk goes up from a waist of 80 cm (31.5 in); for men, from 94 cm (37 in).12

Why are the numbers lower for some groups?

Because South Asian, South-East Asian, East Asian, Aboriginal and Torres Strait Islander people tend to carry more body fat at the same BMI, and their risk of type 2 diabetes and heart disease starts at a lower BMI.1,9 See the Australian cut-offs.

Which blood test shows my diabetes risk?

HbA1c, which shows your average blood sugar over the last 2 to 3 months. 6.5% (48 mmol/mol) or more may mean diabetes, and a result a little below that may mean prediabetes.15 The ranges are under linked health problems.

Can I use these numbers for my child?

No. Adult cut-offs don't apply to anyone under 18. Children's BMI is compared with others of the same age and sex, using a calculator made for children.12,14 See when BMI is misleading.

Does a high BMI mean I need a GLP-1 medicine?

No. BMI and waist describe risk. Medicines have their own approved uses, and a doctor looks at your whole health.1,6 Guide 3 and Guide 4 cover your options and when a medicine may or may not fit.

Before you move on

  • For most adults, BMI 25 is overweight and 30 is obesity.
  • For Asian people, and as recommended for Aboriginal and Torres Strait Islander people, the lines are 23 and 27.5.
  • Check your waist: risk rises from 80 cm (31.5 in) for women and 94 cm (37 in) for men.
  • Clinical obesity means extra fat is already affecting your body.
  • Losing 5–10% of your weight can bring real health gains.
  • These numbers describe risk. They don't decide whether you need a medicine.
Your optionsShould I consider a GLP-1?BMI and waist checker
Was this guide easy to understand?

Sources

  1. Markovic TP, Proietto J, Dixon JB et al. The Australian Obesity Management Algorithm: a simple tool to guide the management of obesity in primary care. Australian Diabetes Society, with ANZOS, ANZMOSS and the RACGP, July 2024. Section 3.1.1 and Table 2 (BMI and waist categories; "Cut-offs apply to Asian population and recommended for Australian indigenous population"), Section 1 (weight bias), Section 4 (older adults) and Appendix 2. diabetessociety.com.au
  2. Australian Bureau of Statistics. Waist circumference and BMI, 2022 (National Health Survey, released 15 December 2023): "Almost two thirds (65.8%) of adults were overweight or obese"; "Three in ten (31.7%) were obese"; 67.9% had a waist putting them at increased risk. abs.gov.au
  3. Knowler WC et al.; Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002;346:393–403. doi:10.1056/NEJMoa012512
  4. Wing RR et al.; Look AHEAD Research Group. Benefits of modest weight loss in improving cardiovascular risk factors in overweight and obese individuals with type 2 diabetes. Diabetes Care 2011;34:1481–6. doi:10.2337/dc10-2415
  5. Vilar-Gomez E et al. Weight loss through lifestyle modification significantly reduces features of nonalcoholic steatohepatitis. Gastroenterology 2015;149:367–78. doi:10.1053/j.gastro.2015.04.005
  6. Novo Nordisk. Wegovy (semaglutide) Australian Product Information, revised 22 June 2026, section 4.1; Eli Lilly. Mounjaro (tirzepatide) Australian Product Information, revised 2 October 2026, section 4.1 (BMI ≥30, or ≥27 with at least one weight-related condition). Wegovy PI · Mounjaro PI
  7. World Health Organization. Obesity and overweight (fact sheet). 8 December 2025. who.int
  8. WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet 2004;363:157–63. doi:10.1016/S0140-6736(03)15268-3
  9. Caleyachetty R et al. Ethnicity-specific BMI cutoffs for obesity based on type 2 diabetes risk in England: a population-based cohort study. Lancet Diabetes Endocrinol 2021;9:419–26. doi:10.1016/S2213-8587(21)00088-7
  10. Diabetes Australia. Diabetes in Australia ("Almost 1.9 million Australians have diabetes … up to 500,000 estimated" undiagnosed; Aboriginal and Torres Strait Islander Australians "three times more likely to develop type 2 diabetes"). Checked 12 October 2026. diabetesaustralia.com.au
  11. Australian Government Department of Health, Disability and Ageing. The Australian Type 2 Diabetes Risk Assessment Tool (AUSDRISK). Checked 12 October 2026. health.gov.au
  12. Healthdirect Australia. Body mass index (BMI) and waist circumference. Last reviewed December 2024. healthdirect.gov.au
  13. Misra A et al. Consensus statement for diagnosis of obesity, abdominal obesity and the metabolic syndrome for Asian Indians. J Assoc Physicians India 2009;57:163–70 (Indian cut-offs, for people living in India). PMID 19582986
  14. US Centers for Disease Control and Prevention. About body mass index (BMI). Updated 16 December 2025. cdc.gov
  15. Healthdirect Australia. HbA1c test ("Diabetes may be diagnosed if your HbA1c result is 6.5% (48 mmol/mol) or higher"). Last reviewed March 2025. healthdirect.gov.au
  16. Rubino F et al. Definition and diagnostic criteria of clinical obesity (Lancet Diabetes & Endocrinology Commission). Lancet Diabetes Endocrinol 2025;13:221–62. The Commission had 58 members; 56 are named as authors. Declared interests: most of the 56 authors declare payments from Novo Nordisk, and many also from Eli Lilly (paper's own declaration). doi:10.1016/S2213-8587(24)00316-4
  17. Batsis JA, Villareal DT. Sarcopenic obesity in older adults: aetiology, epidemiology and treatment strategies. Nat Rev Endocrinol 2018;14:513–37. doi:10.1038/s41574-018-0062-9
  18. National Health and Medical Research Council. Clinical practice guidelines for the management of overweight and obesity (2013 edition marked "Rescinded"); Department of Health, Disability and Ageing, public consultation on new guidelines, closed 16 December 2024. nhmrc.gov.au · health.gov.au
  19. Pharmaceutical Benefits Scheme. Medicine status: semaglutide (Wegovy), document 1460 ("Medicine listed on PBS: Has not yet occurred"), updated 23 July 2026. pbs.gov.au
  20. Lean MEJ, Leslie WS, Barnes AC et al. Primary care-led weight management for remission of type 2 diabetes (DiRECT): an open-label, cluster-randomised trial. Lancet 2018;391(10120):541–551. 306 people in Scotland and England. doi:10.1016/S0140-6736(17)33102-1
  21. Hamman RF et al. Effect of weight loss with lifestyle intervention on risk of diabetes. Diabetes Care 2006;29:2102–7. doi:10.2337/dc06-0560
  22. Rinella ME et al. A multisociety Delphi consensus statement on new fatty liver disease nomenclature. Hepatology 2023. Declared interests: 21 of 53 authors declare consulting, advisory or grant ties to Novo Nordisk and 5 to Eli Lilly (paper's own declaration). doi:10.1097/HEP.0000000000000520
  23. Rubino F et al. Joint international consensus statement for ending stigma of obesity. Nat Med 2020;26:485–97. Declared interests: 15 of 36 authors declare ties to Novo Nordisk and 2 to Eli Lilly; Novo Nordisk was one of the sponsors of the meeting's travel costs (paper's own declaration). doi:10.1038/s41591-020-0803-x

Last checked 12 Oct 2026 · Next review due Jan 2027 · Report an error

How this guide was made. Written by the GLP Guidebook team from the sources above: Australian guidance, national surveys and published trials. It's general information, not medical advice. Talk to your GP or another qualified health professional before starting, stopping or changing any treatment. In an emergency, call triple zero (000). For health advice any time, call healthdirect on 1800 022 222. How we write