If you drink diet soda instead of water or nothing, it won’t help you lose weight or eat less — but if you swap it for sugary drinks, then it might help.

Using sugar-free sweeteners doesn’t make you eat more fat or protein than if you used regular sugar or just drank water—so their main job is just to cut down carbs and calories.

Drinking diet soda instead of water doesn’t make you eat fewer calories — it only helps cut calories if you’re swapping it for sugary drinks instead.

If you swap sugary foods and drinks for ones with artificial sweeteners, you might lose about 1 kg and eat fewer calories—especially if you cut out a lot of sugar. But this only works if you’re replacing sugar, not just adding sweeteners on top.

Using sugar substitutes like stevia or aspartame doesn’t make you more likely to have bad health effects than eating sugar, drinking water, or taking a fake pill—so they’re probably safe if you’re trying to lose weight.

If you swap out sugary drinks and snacks for ones with artificial sweeteners, you might eat about 175 fewer calories a day, which could help you manage your weight.