well... yes and no.

You do subtract the fiber from the total carbs, because those pass right through you. That's the easy answer.

The sugar alcohols, on the other hand... sort of. Technically, they also can be subtracted, but a lot of people find that they act just like a regular carb (only with more gas and diarrhea) and bring weight loss to a screeching halt, so they tend to count the sugar alcohol carbs as regular carbs or just avoid them all together.

There's a bunch of threads about sugar alcohols around that might explain it better.

Hope this helps, and good luck. I'm sorry to hear about your loss