Does adding water to a sugary drink lower the amount of sugar in serving?

Adding water to a sugary drink dilutes the concentration of sugar in the drink, but it does not remove or lower the total amount of sugar. The same amount of sugar is still present, but it is spread out over a larger volume of liquid.

For example, if you have a 12-ounce can of soda that contains 39 grams of sugar and you add 12 ounces of water to it, the resulting 24-ounce drink will still contain 39 grams of sugar. However, the concentration of sugar will be halved, from 39 grams per 12 ounces to 19.5 grams per 12 ounces.

So, while adding water to a sugary drink can make it taste less sweet and may help you consume less sugar overall, it does not actually reduce the amount of sugar in the drink itself.