Learning to count - Net vs Total Carbs

Alrighty, I'm back with another question. What a shocker! Today I was eating my lunch and noticed on my lovely Atkins snack bar a little "tip". It reads:

"Counting Carbs? Fiber, sugar alcohols, including glycerin, should be subtracted from the total carbs since they minimally impact blood sugar."

Excellent! I think... So my main question is this: When you are figuring how much insulin to take do you base it off of the Total Carbs or the Net Carbs (Total Carbs - Fiber - Sugar Alcohols)? Any and all info, opinions , and thoughts are welcome so long as they're positive and constructive! That doesn't seem to be an issue here with most everyone though. =]

This is a great question, awg. I wish I had a consistent answer! For myself, I base my insulin dosage on the Net Carbs of the food the first time or two that I eat it. If it turns out that it wasn't enough to cover the food, I'll try using the total carbs the third time I eat the thing.

But the other thing that makes a difference for me is the time of day that I eat whatever it is. I can only eat a small number of carbs in the morning or I can't keep my BG within range. By mid-afternoon, I can eat more carb. Dinnertime and until bedtime are the easiest for me to eat carbohydrates without spiking unexpectedly. I'm less insulin resistant after about 2:00 p.m. most days.

In the end, I think you'll need to test and see what happens for you. You'll be fine!

I only count the net carbs. That is what works for me. Some folks bolus for the total carbs and that is what works for them. You will have to test to see what works best for you. Good luck.


I read somewhere that you subtract the fiber from the amount of carbs then add half of the amount of sugar alcohols as carbs. They still can cause your BG to go up. I think it was from "Think like a Pancreas." I don't usually eat those anymore though because I haven't found any that taste very good. I'd rather just eat less of the real thing. Let me know if there's something I'm missing!

I don't get away with subtracting the sugar alcohols. To adequately figure it, I have to take the total carbs less the fiber only. Sugar alcohols spike my BG. I think everyone is different.

I go with the rule of subtracting fiber only if it is 5 or more grams. But I think whatever rule you go with, you will end up adjusting your I:C ratio accordingly.

I have to bolus for the total amount of carbs. Subtracting the fiber has never worked for me.

I think there is a lot of different opinions about how to "count" carbs. In then end, all that really matters is estimating the total amount your blood sugar will rise from a given meal. Clearly, if you eat glucose (dextrose), your blood sugar will rise proportionally from the sugar. But other foods are more complicated. We have been told that fiber does not raise your blood sugar and can be subtracted. In fact, the definition of fiber is that it is indigestible. But on closer examination, that definition is totally bogus, in fact you do digest fiber in various ways. In particular, your gut flora ferments fiber and you can absorb part of it. It is well known that much of this fiber is absorbed as short chain fatty acids (SCFAs). I beleive that some non-trivial part of fiber is also absorbed as nutrients that raise blood sugar. At the very least, one would think that fiber should at least be considered as partly fat since it is absorbed as SCFAs.

And then when we look at things like sugar alcohol and glycerin, these are all things that raise your blood sugar. Not as much as dextrose or wheat flour, but in ways that are significant. David Mendosa wrote (years ago) about how to deal with sugar alcohols and carb counting. His view is that you must account for the proportion of sugar alcohols which will lead to a blood sugar rise and that you can subtract the total grams of sugar alcohol, but you must add back in the proportion that contributes to a glycemic load. And while I don't agree with Mendosas assessment of fiber and glycerin, I think he really has a good view on sugar alcohols.

I don’t bother subtracting carbs for fiber.

I haven't heard of many people being able to bolus off of the "net carbs amount." I have always used the total amount, personally. Depending on how you metabolize, the "net effect" may be that the food is either processed slower or faster by your system and that may be telling on how you dose.


When I was diagnosed 3+ years ago, my CDE told me if the fiber was 5 grams or over, to subtract 1/2 from the total carbs. Tried it a few times, but always went high. Now I use total carbs for my calculations.


This sounds like another case of YDMV (Your Diabetes May Vary). Confound this disease for being so "personalized"! Oh well, c'est la D. It's still great to hear from everyone and get their input. Gotta say, there hasn't been a question I've posted where I didn't learn something from the community here. Much thanks to you all!

Diabetesmine talks about sugar alcohols these days (link): he says count them as half.
I don't consider fiber, but I have to consider proteins (meat) if they are more than usual.
Proteins are low to digest, so usually the contribute to BG of your average daily dose of protein is "embedded" in your basal insulin.
But if you eat more than usual proteins, you have to bolus "something more and longer duration". Someone says to calc them as 60% of weight as CHO, for the weight exceeding your usual daily dose.
But this is advanced topic, not something for people starting doing CHO counting and something to know and consider but I don't know if anyone does the actual math .....

Interesting. I have seen discussions like this before, which compelled me to try one of the new net carb pastas. Unfortunately, I agree with many of you: for me, carbs is carbs without subtractions, fiber, etc.

I do find that foods I cannot usually eat (pizza and pasta) are OK if I make them from scratch at home. Pasta (did you ever notice that the amount of carbs listed for 1/8 of a box is nearly the same for every pasta?) is all purpose flour (1 cup=88carbs)and eggs and salt. No problem because I made it, know what I put in it and can get an accurate carb count. One piece of commercial pizza puts my BG into high gear, but I can eat three (although smaller) pieces. I truly feel that good control depends a lot on what you eat, not how you count carbs,

I made an absolutely decadent cinnamon bread a few weeks ago--two loaves. Gave 1.5 loaves away, but was able to eat some of it because I knew exactly what was in it--even the sugar could be counted, No problems.

I agree with you. I do a lot of cooking at home and have a lot more success in carb counting. I measure the ingredients and then write the numbers down in my cookbook for the next time I use the recipe. Whenever people say they can't eat Chinese or Thai food I say, "cook it yourself" - no sugar in sauces, no cornstarch, etc. Stirfries are one of my favorite low carb meals - especially as a vegetarian!