I’ve been told of the “5 or more” rule for fiber, and it personally doesn’t make sense to me. Does this mean that if you eat half a bar (4g fiber) that it counts as more than a full bar (8g fiber?). There are probably some “Sugar alcohols” in there (maltitol, etc) that isn’t listed. Those often get subtracted by marketers to get net carbs.
Just so you know what’s happening, fiber carbs will eventually be turned into sugar, just over a long period of time – long enough that a non-diabetic wouldn’t notice a BG rise. With sugar alcohols, only part of it gets metabolized, and the rest just passes right through you (hence, the warning of a “laxative effect” on the packaging).
What I do – and it’s not perfect, is count the fibers and sugar alcohols as half a gram each. So if what you’re telling me is that the bar has:
14 g total carb
2 g net carb
1 g sugar (this is NOT sugar alcohol, correct?)
8 g fiber
4 g sugar alcohol (my own calculation: the difference between the total and net is 12 g, so if 8 of them are fiber, 4 must be sugar alcohol)
then I would bolus for 8 grams of carbs. 2 for the “net”, and 6 as half of the fiber+sugar alcohol.
I’ve found mixed results with this, though. You may need to square-wave it over an hour because of the way the fiber and sugar alcohols get metabolized. Check your meter and your CGM (if you have one) and refine as necessary.
Personally, I try to avoid the sugar alcohols (limit to no more than 2 per meal) as they are seemingly marketing gimmicks that give me wild BG fluctuations and bad gastrointestinal reactions. Occasionally I’ll treat myself. High fiber is good for you, high sugar alcohol is not.