You know what? I honestly don't know, however, some sugar substitutes are far unhealthier than actual sugar.
If you're going to use a sugar substitute, opt for a natural source like stevia, agave, or black strap molasses (btw, black strap molasses has many wonderful health benefits - see for yourself: http://funadvice.com/r/1687sibcrgg.
At any rate, regardless of whether or not you're going to be consuming sweets, you should be drinking your minimum of 8 glasses of water a day to make sure you're not getting dehydrated.
Little known fact: When the body is dehydrated, it goes into survival mode and stops sending signals that you are thirsty. If you're not thirsty, it means you need to drink.
Hmmm ... that link messed up, it's here: http://funadvice.com/r/1687sjqpr29