The caffeine, which can be a diuretic, will actually make you need to urinate more quickly, and you'll lose more fluid. The myth implies that drinking soda is actually worse than not drinking anything at all. So what's the truth? Soda isn't dehydrating.

Does Sprite count as water intake?

Yes. Sparkling soft drinks, including reduced and no sugar, no calorie options, contain between 85% and 99% water, which means they can help quench thirst and count towards your recommended daily fluid intake.

Can you hydrate yourself with soda?

Sodas, even diet ones, get a bad rap for lacking nutritional value, but they can still be hydrating. Juices and sports drinks are also hydrating -- you can lower the sugar content by diluting them with water.