Ultra low carbing 10-20 carbs a day.

ZipperJJ

Fiber does not affect blood glucose levels. It's not broken down by the body - it just goes in and comes back out. The reason for counting carbs is to monitor how you are affecting your blood glucose levels (which stimulates insulin production which keeps you from using stored fat). That is why you subtract fiber to get your NET carbs. Being that fiber is an important and healthy part of anyone's diet, it would be a shame to avoid foods that are high in fiber for fear that they raise your total carb count. Any foods that are high in fiber but low in sugar/starch (avocado, coconut, chia seeds, flax meal, etc) would be a good addition to anyone's diet.

http://www.joslin.org/info/how_does_fiber_affect_blood_glucose_levels.html
http://www.livestrong.com/article/425146-blood-glucose-insulin-fat-and-losing-weight/

Net carbs with regards to sugar alcohols are a different thing (the net carb count includes the subtraction of both fiber AND sugar alcohols from the total carb count.) Many people do not subtract the sugar alchol count for their net carb count and that is fine - they definitely can raise the blood glucose levels for certain individuals.