There are already plenty of good reasons to cut back on sugar, including slimming your waistline (as part of a lower-calorie diet) and possibly lowering your risk of heart disease. Cutting out sugary drinks, if not sugar itself, is also thought to help lower the risk of diabetes. But here's a new one: Curb your sweet tooth and you may be less prone to develop breast cancer.

Related: Should You Say Sayonara to Sugar?

A study from University of Texas MD Anderson Cancer Center fingers fructose as a breast cancer culprit. Fructose is a component of sucrose, or table sugar, and is "ubiquitous within our food system" according to the researchers. (Think "high fructose corn syrup.")

In the study, mice fed a diet high in sugar were more likely to develop breast tumors — and those tumors were more likely to spread to the lungs. “We found that sucrose intake in mice comparable to levels of Western diets led to increased tumor growth and metastasis when compared to a non-sugar starch diet,” said Peiying Yang, PhD, assistant professor of palliative, rehabilitation, and integrative medicine.

But fructose was the real offender according to co-author Lorenzo Cohen, PhD. “We determined that it was specifically fructose, in table sugar and high-fructose corn syrup…which was responsible for facilitating lung metastasis and 12-HETE production in breast tumors.” 12-HETE is a fatty acid that fuels tumor growth.

Earlier research on large populations suggested a link between a high-sugar diet and breast cancer, with inflammation as a possible culprit.

Related: Are You Eating More Sugar Than You Think?

David Katz, MD, MPH, founding director of the Yale-Griffin Prevention Research Center and author of "Disease-Proof: The Remarkable Truth About What Makes Us Well," explains the new study this way. "High sugar intake has been associated with higher risk of chronic disease in general, and that includes cancer. But a specific mechanism by which sugar would contribute to breast cancer risk, other than a general increase in inflammation, has not been elucidated. This study suggests a specific pathway by which an excess of sugar intake can promote breast cancer via gene expression."

We can't know for sure whether these results apply to humans, but "we have these genes, so it is possible if not probable." Increased sugar intake is already associated with obesity, insulin resistance and diabetes — "which in turn are associated with increased risk of many cancers," says Katz. "So we had reason to cut back on sugar anyway. Does this add another to that list? Possibly — so why take the chance?"

Moderating sugar consumption is critical, the researchers say, considering that each person in the United States consumes more than 100 pounds of it per year. They also note our fondness for sugar-sweetened beverages has been identified as a significant contributor to an epidemic of obesity, heart disease and cancer worldwide.

Related: Break Your Addictive Food Habit

Marianne has been producing content that informs and inspires for more than 20 years, with a deep focus on bringing readers accurate, actionable advice and helping them live healthier, safer lives. Before launching SafeBee, she was executive editor of Sharecare, the health website and social network. Previously, she developed more than two dozen illustrated consumer health books for Reader’s Digest. Her writing has appeared in numerous outlets including Arthritis Today and WebMD. Her favorite safety tip: Know the purpose of every medication you take and under what circumstances you can stop taking it.