A common piece of advice in the battle of the bulge is to replace sugar-sweetened drinks with water or other calorie-free thirst quenchers.
But while that advice is logical, there hasn't been research to show whether changing your drinking habits alone actually works.
So for the new study, researchers randomly assigned 318 overweight adults to one of three groups: one that replaced sugary drinks with water; one that substituted with diet beverages; and one that was given weight-loss advice and could make diet changes of their choice.
After six months, all three groups lost four or five pounds, on average.
But the two groups that cut sugary drinks were more likely to shed at least five per cent of their starting weight: 20 per cent did, versus 11 per cent of the comparison group.
A five-per cent weight loss is considered "clinically meaningful" – or enough to see health benefits, like a drop in blood pressure, said lead researcher Deborah F. Tate, of the University of North Carolina at Chapel Hill.
People who need to lose weight often find a diet overhaul too daunting. But swapping a couple of sweet drinks for sugar-free alternatives may seem relatively easy, according to Tate.
On average, people in this study lost around two per cent of their body weight. That's not huge, but it's a move in the right direction, the researchers say.