Keeping your weight within the healthy range and avoiding weight gain as an adult is an important way to reduce your cancer risk.
Many people don’t realise that being overweight or obese is a risk factor for many types of cancer, including bowel, kidney, stomach, gallbladder, ovary, prostate, pancreas, oesophagus, endometrium, liver, mouth, throat and breast (after menopause).
How does being overweight increase cancer risk?
Researchers are still investigating how being overweight causes cancer. However, there are several possible reasons:
- Too much body fat can cause insulin and other growth factor levels to rise, and this can make cancer cells grow.
- Fat cells release sex hormones that are linked with some cancers.
- Body fat stimulates inflammation that promotes cancer development.
About 4000 cancers diagnosed each year in Australian adults can be attributed to being overweight or obese.
How to check your health risk
The health risk associated with your body weight can be estimated using your waist measurement and body mass index (BMI).
Measure your waist
Having fat around your abdomen or waist, regardless of your body size, increases your risk of developing certain weight-related health conditions, including cancer.
- Place a measuring tape firmly around your waist. For women – measure around the narrowest point of your waist. For men – measure around your navel
- Make sure you breathe normally.
- Use the table below to determine your health risk
|Risk of cancer, heart disease and diabetes||Waist Measurement (cm)|
|Increased||80cm or more||94cm or more|
|Greatly increased||88cm or more||102cm or more|
Calculate your BMI
BMI is a simple way to find out if you are a healthy weight for your height. Work out your BMI by dividing your weight in kilograms (kg) by your height in metres squared.
|Body mass index||Category|
|Less than 18.5||Underweight|
|Between 18.5 and 25||Healthy weight|
|Between 25 and 30||Overweight|
|More than 30||Obese|
How to maintain a healthy bodyweight
The amount of energy in food or drink is measured in kilojoules (kJ).
If you eat and drink more kilojoules than your body uses through metabolism, exercise and day-to-day activities, the spare energy is stored as fat and you put on weight.
Factors that can lead to weight gain include:
- having too many unhealthy foods and drinks high in kilojoules, added fat or sugars, e.g. sugary drinks, takeaway foods, potato chips, pies, cakes and sweets
- having large food portions or eating more often than your body needs
- not doing enough moderate or vigorous physical activity
- being too sedentary, e.g. watching television or using computers for long periods of time.
To achieve and maintain a healthy body weight, eat a balanced diet and do regular physical activity.
If you are above a healthy weight, focus on making realistic and long-term changes to your current eating and activity patterns.
Avoid fad diets and extreme exercise plans. Being active and following a healthy eating and drinking plan most of the time is a good start. If you need more help, see your general practitioner (GP) or find a dietitian.