Cancer Research UK said Wednesday that more than 100,000 cancers in the UK - one third of the country's total diagnosed each year - are caused by smoking, unhealthy diets, alcohol, and excess weight.

When accounting all 14 lifestyle and environmental risk factors analyzed in the study, the figure increases to around 134,000.

Researchers have found that smoking is by far the most important lifestyle factor causing cancer. Smoking leads to nearly one in five cancers, with the percentage of cancer caused by smoking in men being 23 percent, and for women being 15.6 percent.

Overall, researchers said 45 per cent of all cancers in men and 40 per cent of all cancers in women could be prevented.

“Many people believe cancer is down to fate or ‘in the genes’ and that it is the luck of the draw whether they get it,” said study author professor Max Parkin, a Cancer Research UK epidemiologist based at Queen Mary, University of London.

Parkin said that they didn’t expect to find that eating fruits and vegetables was so important in protecting men against cancer and they didn’t expect to find that being overweight among women would have a greater effect than alcohol.

“In most cases cancers have multiple causes – for example a cervical cancer can be linked to both HPV infection and smoking. This means it isn’t possible to add up the effects of different lifestyle factors -you’d get more than 100 per cent,” Parkin said.

The study was published in the British Journal of Cancer

While the authors explained that one in 25 cancers are linked to occupation and one in 33 to infections, they estimated that tobacco smoking, dietary factors, drinking alcohol and bodyweight account for 106,845 or 34 per cent of cancers occurring in 2010.

Sara Hiom, director of information at Cancer Research UK, said, “We know, especially during the Christmas party season, that it is hard to watch what you eat and limit alcohol and we don’t want people to feel guilty about having a drink or indulging a bit more than usual. But it’s very important for people to understand that long term changes to their lifestyles can really reduce their cancer risk.”

Dr Harpal Kumar, Cancer Research UK’s chief executive said that living a healthy life does not guarantee that a person won’t get cancer but he explained that the study shows how “healthy habits can significantly stack the odds in our favor.”

“While we have made tremendous progress in improving the chance of surviving cancer during the last 40 years, we need to make sure people are made aware of the risks of getting the disease in the first place so they can make the healthiest possible lifestyle choices,” adds Kumar.

“We know that cancer risk can be affected by family history and getting older, but these figures show that we can take positive steps to help reduce our risk of the disease. Stopping smoking, eating a balanced diet, cutting down on alcohol and maintaining a healthy weight could be New Year’s resolutions that help save more lives in future.”

Parkin said that after “Looking at all the evidence, it’s clear that around 40 per cent of all cancers are caused by things we mostly have the power to change.”