“Overweight women are more likely to develop breast cancer than lean ones”

Or so says a recent issue of The Economist (27 November 2010)

The explanation is not easy to follow – but Kevin Gardner at America’s National Cancer Research has found that the processing of calories negatively affects a tumour-suppressing protein.

Furthermore, too much fat also stimulates the production of oestrogen in fat-storage cells. This results in more cell proliferation, increasing the risk of cancer.

“Though this is the first clear link between calorie intake and cancer that has been seen at the molecular level, Dr Gardner says his result is consistent with numerous past experiments … So along with all the other reasons to keep trim, there is a new one: it may help to keep you free of cancer.”

I recommend exercise.

Start with a small amount, and, with time, increase it.