Body weight

Two in every three (67%) Australians adults are either overweight or obese. Being overweight or obese increases your risk of developing chronic diseases such as type 2 diabetes, heart disease and some cancers, including breast cancer (in postmenopausal women), bowel cancer and pancreatic cancer.

Poor food and drink choices and not being active enough can lead to weight gain. Good nutrition and regular physical activity help you to maintain a healthy weight, and reduce your risk of cancer.

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How do I know if I am overweight or obese?

There are two ways you can find out if you are overweight or obese. One is the body mass index (BMI), the other is waist circumference measurements. Neither method is perfect but when used together they are useful in determining how healthy your weight is.

Body Mass Index (BMI)

BMI compares your weight to your height.  BMI is calculated by dividing your weight in kilograms by your height in metres squared. If you enter your height and weight below, you can calculate your BMI.

Height: centimeters   178 centimeters
Weight: kilograms  75 kilograms


BMI: kg/m²

Classification BMI Health risk
Underweight Less than 18.5  
Healthy Weight Range 18.5-24.9 Average
Overweight 25.0 or more  
Overweight 25.0-29.9 Increased
Obese I 30.0-34.9 Moderate
Obese II 35.0-39.9 Severe
Obese III 40 or more Very severe

Source: World Health Organization, 2004.

Note: The BMI may not be accurate for people with greater muscle mass (such as athletes) or in older people and others who have lost muscle mass.

If your BMI is between 18.5 and 25, you are in a healthy weight range.  You should continue to maintain your weight.

If your BMI is above 25, you are above the healthy weight range.  This puts you at a higher risk of developing cancer and other chronic diseases. Try to look for ways to improve your diet and increase your activity levels. Remember, every small change you make counts!  Refer to some of the healthy eating and exercise tips on our website to help you work towards a healthy weight range to reduce your risk of cancer.

If your BMI is below 18.5, you are below the healthy weight range. Being underweight puts you at risk of poor health.

If you require professional advice on managing your weight, consult your doctor or an Accredited Practising Dietitian to help you achieve a healthier weight.

Female waist circumference measurementWaist circumference

Waist circumference indicates how much fat you have around the middle of your body or abdomen (stomach). Having weight around your middle is a risk factor for many chronic diseases, including some cancers, type 2 diabetes and cardiovascular disease. It is more of a health risk than the weight on your hips or thighs.

Use a measuring tape to measure your waist circumference around the narrowest point of your body (see diagram). Measure at the end of a normal breath, and ensure that the tape is firm; not too tight or too loose.

You may be at a higher risk of developing cancer if your waist circumference is above the healthy range.

Male waist circumference measurement


  • 80 cm or more increases risk
  • 88 cm or more substantially increases risk


  • 94 cm or more increases risk
  • 102 cm or more substantially increases risk

Source: World Health Organization, 2000.