And not just any kind of breast cancer, either. It's a particularly dangerous kind.
The findings, published in the American Journal of Clinical Nutrition and conducted the by International Agency for Research on Cancer in France, reveal a link between these types of carbohydrates and a less common form of breast cancer known as "ER-Negative."
"This study gives us a really important clue for future research," says Christina Clarke, a research scientist at the Cancer Prevention Institute of California in Fremont, who adds that little is known about what causes this type of cancer since most breast tumours feed off estrogen, but the ER Negative tumor does not.
This makes it a deadlier form of the disease as the tumours tend to grow faster and do not respond as well to hormone-based treatments.
The results come after years of research focused on how nutrition affects cancer risk.
In Canada, there are 22,700 women and 200 men currently diagnosed with breast cancer.
Aside from non-melanoma skin cancer, it's the most common form of cancer among Canadian women, with one in nine women expected to develop it in her lifetime.
In this most recent study, scientists analyzed data from 335,000 European women and discovered a link between a high "glycemic load" and the estrogen-deficient tumours.
They found that 158 postmenopausal women in the top 20 per cent for glycemic load had developed the ER-negative breast cancer, versus 20 cases diagnosed in the bottom 20 per cent.
An elevated glycemic load, or spike in blood sugar, is often caused by a diet high in processed foods and unrefined carbs.
Among the worst offenders? Potatoes, white flour and sugary treats because as they raise blood sugar levels they also raise insulin levels. And high levels of insulin have been linked to certain forms of cancer.
The study comes on the heel of similar research that found increased starch and carbohydrate intake increased the risk of breast cancer recurrence in survivors.
Though the scientists claim there are numerous factors that contribute to breast cancer risk, the findings are simply another good reason to put down the half-priced muffins and head for the fruit and vegetable aisle.