It is now well known that women who develop early breast cancer do tend to put on weight during their treatment. This is particularly true of younger women under the age of 50.

There are a number of causes for this tendency to put on weight. These include:

• an early menopause - many women under the age of 50 having chemotherapy will have a temporary (and sometimes permanent) early menopause and there is a natural tendency to put on weight during the menopause because of the hormonal changes that take place

• change in diet - there is good evidence from a number of studies that women who are newly diagnosed with breast cancer tend to alter their diet and are likely to eat more than they did before the breast cancer was discovered

• lack of exercise - other studies have also shown that during treatment for early breast cancer many women reduce their exercise levels.

• steroids used during chemotherapy to prevent side effects – one side effect of steroids is weight gain

• tamoxifen - many women with early breast cancer are advised to take the drug tamoxifen and this can often lead to an increase in weight

In terms of self-help the two most important things are to keep to a sensible diet and, if at all possible, to take regular exercise.

Diet is a very personal matter but concentrating on fresh fruit and vegetables and avoiding too much in the way of fatty and starchy foods is always good advice. It can help to keep a watch on your weight and diet during treatment and it usually isn’t harmful to do some gentle dieting afterwards, if necessary. Your medical team, including a dietitian, will be able to give you more detailed advice on diets and dieting.

Exercise is also going to help. This doesn't need to be vigorous but if you can keep active during treatment (with things like regular walking or cycling) this can help to reduce the risk of putting on too much weight and there is some evidence that keeping fit in this way also reduces unpleasant side effects of chemotherapy like nausea and tiredness.