Well... it is a fact that fiber goes right through you. That you can definitely subtract.

There is a debate when it comes to other "indigestible" carbs. Glycerine, maltitol, sorbitol, etc. affect some people as if they are carbs. The only way for you to know how YOU do, is to experiment. Weigh your options. Generally, I do fine with them, but try to avoid them as much as possible due to all the horror stories.

Try reading the quick link to your right "The truth about low carb sweeteners info".