:: Undertake some brisk, physical activity every day

In this section, the adverse effect of obesity (or being overweight) and the protective effect of exercise on cancer risk are summarised. It is based on the evidence from a comprehensive review on weight control and physical activity published by the International Agency for Research on Cancer. Because of the relationship between obesity and physical activity it is important to separate the effects of the two.

Physical activity.
Many studies have examined the relationship between physical activity and the risk of developing cancer. There is consistent evidence that some form of regular physical activity is associated with a reduction in the risk of colon cancer. There is also a suggestion of a risk reduction in relation to cancer of the breast, endometrium and prostate. The protective effect of physical activity on cancer risk improves with increasing levels of activity - the more the better - though such a recommendation should be moderated in individuals with cardiovascular disease. Regular physical activity that involves some exertion may be needed to maintain a healthy body weight, particularly for people with sedentary lifestyles. This could involve half an hour per day three times per week. More vigorous activity several times per week may give some additional benefits regarding cancer prevention.

For some cancers, the preventive effect of regular physical activity seems to act independently of weight control. The prevention of weight gain and obesity and the promotion of exercise ideally should begin early in life. However, the benefits can also be gained later in life if a healthy lifestyle is adopted. It is desirable to maintain a BMI in the range of 18.5 to 25 kg/m2 and people who are already overweight or obese should aim to reduce their BMI to below 25 kg/m2. A lifestyle that incorporates a healthy diet, exercise and weight control is beneficial to the individual not only with regards to cancer but also other diseases.