Sure, the idea of getting your sugar fix without the calories always seems enticing, but new research suggests that Splenda—an artificial sweetener recently considered safe—may contribute to serious health problems like cancer.

The study, published in the International Journal of Occupational and Environmental Health, found that mice fed sucralose daily throughout their lives developed leukemia and other blood cancers. In response to the findings, the Center for Science in the Public Interest—a nutrition watchdog group that assesses the safety of food additives—has now formally recommended that consumers avoid the sweetener. That’s a big deal, considering that until 2013, they’d rated the additive as “safe.”

This new evidence was especially powerful because it was funded without special interests in mind, explains Lisa Lefferts, MSPH, senior scientist at the CSPI. “For most food additives, the safety studies are conducted by the manufacturers who have financial incentives,” Lefferts says. (Here’s why industry funding in nutrition studies is such a huge problem.)

Granted, the doses of sucralose used in the study were equivalent to someone drinking at least 10 cans of diet soda per day—tough for anyone to do, but not totally out of the realm of possibility if you’re consuming artificial sweeteners from multiple food and drink sources. “And even if you consume less, that doesn’t mean there’s no problem,” Lefferts says. “When something causes cancer at high doses, it generally causes cancer at lower doses, the risk is just smaller.”

But even if you discount this new mouse study, you’ll still find plenty of reasons to skip out on sucralose. A growing body of research shows that artificial sweeteners may actually cause weight gain, not weight loss. One study found drinking diet soda was linked to increased belly fat; in another, each daily can was associated with a 41% jump in obesity risk. Sucralose has even been shown to mess with your blood sugar and insulin levels, causing spikes and dips that could lead to cravings later on.

The bottom line: the scientists at the CSPI firmly believe you should steer clear of sucralose. But that doesn’t mean you should start shoveling spoonfuls of regular table sugar, either. Instead, try safer stevia extract or any of these 10 genius ways to sweeten without sugar or artificial sweeteners.