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Weight and cancer: What is the link?

Let’s take a closer look at the science behind how being above a healthy weight may cause cancer and find out what we can do to achieve and maintain a healthy weight.

Video: Weight and cancer: What is the link?

Being above a healthy weight, poor diet and lack of physical activity are the most important modifiable risk factors for cancer after tobacco and UV exposure in Australia. The link between obesity and cancer is complex; however, there is strong evidence that being above a healthy weight is a risk factor for some cancers. Excess body fat (especially toxic or visceral fat around the waist and vital organs) leads to more chemicals and hormones being released. It may also lead to inflammation. 

Having inflammation or an excess of these chemicals and hormones can alter how the cells in your body divide, which can increase the risk of cancer.

Which cancers are linked to weight?

Research has shown that 13 types of cancer are more common in people who are above a healthy weight, including cancers of the oesophagus, breast, liver, gallbladder, kidney, bowel, multiple myeloma, meningioma, thyroid, gastric cardia, pancreas, ovaries and uterus.

What is my risk of cancer if I’m above a healthy weight?

Around 30% of cancer cases in Australia are thought to be preventable. The good news is that taking a few simple steps can make a big difference. By eating healthy foods, moving more and preventing more weight gain you can reduce your risk of certain types of cancer and other chronic diseases, such as type 2 diabetes and heart disease.

Take our lifestyle quiz to help you understand where your risk lies and receive personalised tips and challenges to motivate you to make small but significant healthy lifestyle changes.

Take the quiz

What leads to people being above a healthy weight?

Video: Gradual weight gain between early & mid-adult life increases obesity-related cancer risk

Becoming overweight or obese happens gradually as a result of either:

  • consuming more energy (kilojoules from food and drinks) than your body needs
  • consuming more energy (kilojoules from food and drinks) than your body uses by being active.

It’s important to also note other factors can also lead to weight gain, like:

  • the genes you inherit from your parents
  • increasing age and different life stages (for example pregnancy or menopause)
  • certain diseases
  • your surroundings (such as food supply, increased portion size, workplace, sleep, built environment)
  • psychological factors such as stress and underlying personal issues can lead to a lack of energy and motivation and increased food consumption (e.g. emotional or comfort eating), which may indirectly contribute to weight gain.
  • how well your body turns food into energy (your metabolism).

How could being above a healthy weight lead to cancer?

Firstly  What is toxic fat?

Latest research shows that body fat is not just stored under the skin it is also stored deep inside our bodies, including on our organs. This is called visceral fat.

Fat tissue produces chemicals and hormones which travel around our bodies. Visceral fat produces more of these chemicals than the fat under our skin. These chemicals can be damaging to our body. That’s why we call it toxic fat.

Excess body fat (especially toxic fat around the waist and vital organs) may also lead to inflammation.

Having inflammation or an excess of these chemicals and hormones means that your cells might not divide correctly and they might produce abnormal cells. The production of these abnormal cells make cancer more likely to grow.

Find out more

For more information on the link between weight and cancer and about how to reduce your risk of 13 types of cancer download our fact sheet.

If you require more support speak to a doctor, dietitian or call 13 11 20.

Visit LiveLighter for healthy lifestyle tips.