Overweight Cancer Risk

What being Overweight Means for Your Risk of Cancer

By Tracey Walton wlr team

Many of us understand that being overweight can affect our health in a great number of ways. The health risks we are most likely to acknowledge are type II diabetes and heart disease.

However, according to Cancer Research UK, as little as 3% of the British population realise that a body mass index above the healthy range (25 and over) can greatly increase your risk of cancer.

This lack of awareness is particularly worrying to health professionals as being overweight is a major preventable risk factor for cancer.

Professor Jane Wardle, Health Behaviour Unit Director – Cancer Research UK says: “Excess body body fat is not harmless ‘extra padding’, but active tissue producing hormones that can increase the risk of cancer.”

You can find out your own body mass index with the BMI Calculator.

The Evidence Mounts Up

A recent (2018) large scale study led by Spanish researchers has concluded with some shocking results regarding overweight, obesity and the risks of developing cancer and heart disease.

Key Takeaways

  • Women in the obese category have a 12 times greater risk of developing cancer than those of normal weight, and are 5 times more likely to suffer cardiovascular disease
  • Men classed as obese are twice as likely to develop some type of cancer, however do not have a significantly increased chance of developing cardiovascular disease.

The Study

Researchers from the Hospital del Mar Medical Research Institute and doctors from Hospital del Mar analysed the follow up of 54,446 people from 7 different communities over a 10 year period.

 Of the men and women (aged 35 to 79), 25,000 were overweight and 15,000 were obese.

The results of the study are clear, and that is that obesity has a much greater impact on women's health than men's.

What the Researchers are Saying

Dr Jaume Marrugat, a principal investigator of the study felt this research has shown that ‘the improvements in cardiovascular risk factors achieved over the last 20 years are dramatically neutralised by the obesity epidemic’.

It is already well known that being obese increases the risk of cancer and heart disease. However, this study has shown that any increment in body mass above recommended levels results in increased risk of adverse health effects.

So it's not just those in the ‘obese’ category that should be concerned about the health risks; it is also those who are in the ‘overweight’ category.

Dr Albert Goday, an endocrinologist at Hospital del Mar and one of the authors of the study wants to remind people that ‘obesity is a potentially serious medical condition that determines an increased risk of death from various causes’.

However, on a more positive note those who are classed as ‘obese’ can reduce their risk of developing life threatening diseases by simply losing weight, even small weight reductions result in huge health benefits.

As an example, in a country where the average life expectancy is 80, overweight people who lose 5 kilos (11lbs) in their 40s and keep it off, reduce the risk of suffering cardiovascular disease by 20%.

For women, this could also reduce the chance of developing cancer by 20%.

Major Previous Study

A previous study published in The New England Journal Of Medicine found an increased risk of all types of cancer (to varying degrees) in those with a body mass index above the healthy range.

Over 900,000 adults were studied (404,576 men & 495,477 women). All were free of cancer on enrolment in the study in 1982, and during 16 years of follow up there were 57,145 deaths from cancer. Conclusions were drawn for all individual types of cancer based on sex and BMI.

At the top end of the scale (body mass index of 40+), men had a 52% higher combined risk (risk across all cancers) compared with those of a healthy weight, and women a 62% higher risk.

The study found, quite consistently, that with almost all forms of cancer, as BMI went up, so did the risk. More specifically, BMI had a greatly significant correlation to death rates when it came to cancer of the oesophagus, colon, stomach, liver, gallbladder, pancreas, prostate (in men), and breast (in women).

The study concluded that in the U.S., more than 90,000 deaths from cancer could be avoided each year if people remained a healthy weight throughout their lifetime.

What all this tells us is that we can have some control! In the same way as a person has a choice when it comes to smoking cigarettes, we also have a choice when it comes to our lifestyle – more importantly our weight.

Cancer Research UK have released these results to increase awareness that there is something we can do to help prevent ourselves from being at high risk of contracting cancer… Maintain a healthy weight!

Calculate Your BMI

BMI can be calculated (easy with the calculator here) by dividing your weight in kilograms by your height in metres squared.

Body mass index (BMI) = weight(kg) ÷ height(m)2

BMI <18.5 Underweight
BMI 18.5-25 Healthy Weight
BMI 25-30 Overweight
BMI >30 Obese

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Other Useful Info:


Information on all types of cancer.

New England Journal of Medicine

Short summary of the study from the New England Journal Of Medicine.

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