Low-calorie sweeteners have long been controversial for those trying to eat healthy and lose weight because, much like with eggs or coffee, studies have seen conflicting results. But new research published in Cell Metabolism offers some solid evidence that they won’t sabotage your health or weight-loss plan by themselves.

While no one ever complains about having a deliciously sweet diet soda from time to time, some past studies have found that the low-cal sweeteners in food and drinks can mess with your metabolism, affect the way your brain responds to sugar, and promote diabetes and obesity. Still, others have suggested that they don’t impact metabolism and are a good alternative to calorie-laden sugar.

The new research from Yale University researchers found that drinks containing sucralose (a common low-calorie sweetener found in everything from drinks to protein bars) only negatively affected the body’s sugar metabolism and the brain’s responses to sugar when they were consumed along with carbohydrates.

Participants had “seven low-calorie drinks, each containing the equivalent of two packages of Splenda, over two weeks,” senior author Dana Small, professor of psychiatry and psychology and director of the Modern Diet and Physiology Research Center, explained in a release.

One previous theory was that when people consume sweet foods and drinks with no calories, the body “uncouples” tasting something sweet with taking in calories, lowering the body’s response to sugar intake and possibly leading to weight gain.

But when people drank a beverage with a low-calorie sweetener and didn’t accompany it with carbs, there was no negative change in the way the body responds to sugar.

“The bottom line,” Small said, “is that, at least in small quantities, individuals can safely drink a diet soda, but they shouldn’t add French fries.”

So next time you’re at the drive-thru window at your favorite burger chain, go ahead and order that diet soda confidently—just skip the fries and opt for a lettuce bun.