Obesity is known to be a risk factor for some types of cancer, such as bowel, breast and colon cancer. You should try to maintain a healthy body weight by taking regular exercise in addition to eating a healthy diet. Take a look at our body mass index (BMI) calculator to find out if you are over your 'ideal' weight, and to get tips on how to lose weight safely. See the 'further information' section for more information. If you are overweight and want to lose weight safely, your GP will also be able to provide advice.