Links between weight and cancer   

WCRF UK recommends being as lean as possible without becoming underweight.

Maintaining a healthy weight is one of the most important things you can do to reduce your risk of cancer. Aim to be at the lower end of the healthy Body Mass Index (BMI) range.

Maintaining a healthy weight brings a range of health benefits. As well as making us feel better, it also means that we are less likely to develop not only cancer, but also other chronic diseases such as Type 2 diabetes and heart disease.

What is a healthy weight?

One of the easiest ways to check if you’re a healthy weight is by measuring your Body Mass Index (BMI), which is a useful guide for most adults.

A healthy BMI for both men and women is between 18.5-24.9. For cancer prevention, we should aim for the lower end of this range.

We also know that where we store extra weight affects cancer risk. Scientists have discovered that carrying excess fat around our waists can be particularly harmful – it acts like a ‘hormone pump’ releasing oestrogen into the bloodstream, as well as raising levels of other hormones in the body.

This is strongly linked to bowel cancer and probably linked to cancers of the pancreas and endometrium (womb), as well as to breast cancer (in postmenopausal women).

Find out about our other Recommendations for Cancer Prevention

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Body fat and cancer – the evidence

The evidence that being overweight increases risk of cancer is stronger now than ever before. In fact, scientists now believe that, after not smoking, maintaining a healthy weight is the most important thing you can do for cancer prevention.

There is convincing evidence that excess body fat increases risk of cancers of the

• Bowel
• Oesophagus
• Pancreas
• Kidney
• Endometrium (womb)
• Breast (in postmenopausal women).

Being overweight also probably increases the risk of gallbladder cancer.

Scientists believe there are several reasons for the link between body fat and cancer. One example is the relationship between excess fat and the hormonal balance in the body. Research has shown that fat cells release hormones such as oestrogen, which increases the risk of cancers such as breast cancer.

Ways to maintain a healthy weight

• Choose foods lower in energy density which means they have fewer calories for their weight but are filling because they contain plenty of water and fibre.
• Being physically active helps burn calories, which are stored as fat if they are not used up. One way of becoming more physically active is to sign up for a WCRF UK running event
• Avoid fast food and sugary drinks and watch out for high energy-dense foods
• Keeping an eye on portion sizes is one of the best ways to maintain a healthy weight. Too much of any food can cause us to gain weight, so only eat when you’re hungry and try to stop before you feel full. Opt for the smallest serving size available to make it easier to control how much you’re eating.

Find out about our other Recommendations for Cancer Prevention

How can you help WCRF UK?