Evidence suggests that around half of all cases of cancer diagnosed in the UK could be avoided if people made changes to their lifestyle.

Smoking - Smoking tobacco is the greatest risk factor for cancer - it causes more than one in four cancer deaths and has killed six million people over the last 50 years. Smoking is a major cause of lung cancer and is a factor in other cancers, such as bladder cancer and cancers of the mouth and throat.

Body weight - Being overweight is known to increase the risk of cancer. The healthy weight range is based on a measurement known as the Body Mass Index (BMI). This is determined by a person’s weight and height. In the UK, up to about 12,000 cases of cancer (more than four per cent of all cases) could be avoided if no one exceeded a Body Mass Index of 25.

Physical activity - Independent of body weight, people with higher levels of physical activity have a reduced risk of colon and probably breast cancer.

Diet - While it is currently not possible to pinpoint exactly what constituents of diet are protective against cancer, there is a consensus that diet is an important component of cancer risk. Research has suggested that eating a balanced diet, which contains plenty of fruit and vegetables, can help to prevent cancer.

Sunlight - Excessive exposure to ultra-violet radiation is the most important modifiable risk factor for both malignant melanoma and non-melanoma skin cancer. However, it is important to bear in mind that sunlight is an important source of vitamin D, which help us to build and maintain strong bones and teeth, amongst other functions in the body.

Occupation - Contact with certain harmful substances in the workplace can cause cancer. Most known occupational carcinogens are either banned or well regulated within the UK and the majority of occupation-related cancers diagnosed in the UK today are the result of people being exposed more than 10 years ago. We know, for example, that nine out of 10 people who develop mesothelioma (a rare type of cancer affecting the lining of the lung and abdomen) have had contact with asbestos.