Weight and cancer - is there a link?

YES - New evidence shows that too much fat in our body increases the risk of developing 13 different types of cancer

The reason why we develop cancer is something that concerns people in general as well as cancer researchers. Often there is a combination of risk factors – some that are known to us and others that are still unknown. Over the years there has been increasing evidence of a link between cancer and weight and it has been found that people who are overweight or obese have an increased risk of getting certain types of cancer compared to people who have a healthy weight. We say that people have a healthy weight if their body mass index (BMI) is between 18.5 and 24.9. Generally, we say that people are overweight if their BMI is 25 – 29.9 and people are defined as obese if their BMI is 30 or over. BMI is calculated from our weight and height but in children and young people up to 18 years old, the BMI calculator must also take into account the age and gender of the person. There are easily available BMI calculator tools, such as this one on the NHS choices website.

Because our weight is something that we can control to a large degree, it is very useful to know more about the link between cancer and weight. Research in this area are usually studies that look at large groups of people to try and find whether people who are overweight or obese are more likely to develop cancer. Because we know that cancer can be caused by many different factors, these studies will also collect information about other things in people’s lives, for example whether they smoke, exercise and how healthy their diet is.

Because this type of research involves many factors in people’s lives that the researchers can’t control, each individual study can’t really prove whether being overweight and obese can actually cause cancer. But if we look at all such studies together and thereby ‘pile’ the evidence, there is a stronger case for saying that carrying too much weight can actually cause certain types of cancer to develop.

A group called the “International Agency for Research on Cancer (IARC) has done just that and back in 2002 they published a report stating that they had found enough evidence to say that being overweight increased the risk of developing 8 types of cancer. Then in April 2016, the group met again and looked at all the new research that had been done since 2002. After having looked at all the new evidence too, the IARC group published a new report stating that there is now enough evidence to say that being overweight or obese increases the risk of developing 13 different types of cancer. These cancer types are: Oesophagus cancer (food pipe), gastric cardia cancer (a type of stomach cancer), bowel cancer, liver cancer, gallbladder cancer, pancreas cancer, breast cancer, womb cancer, ovarian cancer, kidney cancer, meningioma (a type of brain tumour), thyroid cancer and multiple myeloma (cancer of the white blood cells). We can only say that overweight and obesity increase the risk of getting these types of cancer, we can’t say that being overweight or obese is what has definitely caused the cancer to develop.

These finding mean that it’s even more important to look after our health and make sure that we have a healthy diet and lifestyle so that we don’t put on too much weight. Excess body weight also increases our risk of heart attack and stroke so there is a lot to gain from staying at a healthy weight. Why not check out the NHS’ guidelines for physical activity for children and young people and get tips on food and diet here to see what you can do yourself to keep healthy.

You can read more about the research on links between weight and cancer from the NHS Choices website.

This article was first published : 14.9.2016