It's not the first time experts have claimed being overweight may put you at a higher risk for breast cancer, and it's almost certainly not the last. But researchers from the Institute of Cancer Research in London are currently looking into the specifics - for instance, how much weight you should lose and when, and how much of a part exercise plays.
If women who are overweight or don't take much exercise start changing their lifestyle now, it could help prevent thousands of cases of breast cancer in the future, he says.
If that's not a good enough reason to shed those excess pounds - or perhaps to make sure you don't gain any winter weight this year - we don't know what is.
Professor Swerdlow admits that other factors - having children, for instance, which affects your hormones - are also believed to reduce a woman's risk of breast cancer. But it's not exactly practical to change your plans for having a family just to reduce your likelihood of developing breast cancer, is it?
And that's why the professor believes losing weight and exercising more is the best way forward.
Would the threat of breast cancer in years to come encourage you to step up your weight-loss efforts? Have you already made lifestyle changes to avoid a health problem? Tell us all about it.