How do you carb count?


I’ve heard different opinions on counting carbs. Specifcally, how do you factor in fiber.

I have a T1D relative who says he subtracts ALL the fiber from total carbs. I aslo read a book saying the same.

However, a dietician certified in diabetes (whatever you call them) told me to only subtract fiber if it’s more than 4 gr, and you should only subtract half of the fiber (e.g., 5 grams of fiber you subtract 2.5 from total carbs). I’ve heard some don’t subtract fiber at all, and some even dive real deep into sugar alcohols and more.

Curious about what everyone does/the philosophy they follow. Thanks!

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@JakeVA ,

CDEs, CEDES, or whatever they are called now are a closed shop group like faces. We all have one and they are all different. I was taught 20+ years ago by 3 CDEs, endo’s CDE nurse pump trainer, Animas CDE nurse pump trainer, & Dexcom’s CDE nurse pump trainer. The three nurses assured when I counted carbs, every carb was counted. I asked about fiber & sugar alcohols. The three taught if it a carb, count it as a carb.

I use three carb indexes for foods, CalorieKing, MyFitnessPal, and the food or restaurant web. What ever the carbs is what I put in my pump. Has worked so far very well and I don’t need to do funky math counting this, excluding that. I recently saw a dietician with a different specialty. She was preaching “net carbs”. In all my years of training & retraining every time I changed pumps, I learned one thing. If a dietician starts with anything about “net carbs”, they are preaching snake oil and are forever lost.

Hope this helps.


Like @987jaj I was taught that “a carb if a carb” and I’ve never subtracted out fiber. What are you doing, and how is it working for you?
If I were going to experiment (and I’m not) I would first see how it works without subtracting any, then try the other extreme of subtracting all; and if that yielded vastly different results and neither got me where I wanted, then I would try the formula and see how it works (but first my question for the nutritionist would be where did you get that formula?)
To make the experiment as accurate as possible I would have to eat the same meals for a few days with each method and try to keep other variables such as exercise and stress, the same.

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Dorie, my training & retraining has need wonderful using “a carb is a carb is a carb” with none of the net carb malarkey.

When I would visit a Cracker Barrel Old Country Store to eat & ask for a nutrition guide, I would be given a menu list with only net carbs.


I should have added that the dietician said the research is mixed on carb counting for fiber and IF you deduct fiber, only do half of the fiber over 4 grs. She also loathes the marketing term “net carb.” It’s for Keto (which is another can of controversial worms).

I haven’t really seen a difference either way. I know certain foods don’t spike me, but those are usually non-starchy veggies and nuts/peanut butter.

Bread or granola bars or cereals with high fiber over 4gr still raise me all the same. So I think it’s all personal or at least your matching your ratio consistently whether you deduct or not. I don’t pay much attention to them at this point, I just do total carbs and exclude certain foods from my total.

Hi @JakeVA I don’t think there is a “right” answer here I think you should do what works for you. If you eat consistent fiber and you wanna subtract all of them then you will end up with a carb ratio that makes it possible. If you do something different you will end up with a carb ratio that makes it possible. I generally use “grams carb” and modify for fats (more fats need more insulin over a longer time) and activity (more activity needs much less insulin). So while I don’t know the right answer, I do know what works for me. Good luck :four_leaf_clover:

Mostly you’re only dealing with a few grams of fiber so you could try subtracting them and if the sugar runs higher than expected put them back the next time and see how that goes…

I’m confused as to why this is snake oil/malarky - any enlightenment would be helpful. My understanding is that fiber is not digested. If it is not digested, glucose is not extracted. If glucose is not extracted, it cannot affect blood sugar. ?

@BKN480, although the carbohydrates are not truly metabolized, there is enough entry of the fiber into the digestive process to create glucose alteration in insulin demand.

For example, if I eat an Abbott Zone Perfect Bar with zero fiber & 24 grams of carbs, dosing accordingly, I come out fine. On the flip side, if I eat soup beans & subtract the fiber, my insulin dose is insufficient to prevent a return to a pre meal level 3-5 hours later. The lack of return means the fiber entered my metabolic pathway somewhere, somehow.

My training team members over the years have shared my example is seen frequently enough to teach ‘net carbs’ need inclusion in the insulin dosage calculations. The training team over the past 20+ years has included 6 RN pump training CEDES. (CDEs) representing my endo, Animas, Dexcom, & Tandem.

The consensus of my team was if someone leads in with ‘net carbs’ watch out for the snake oil carnival barker.

I will also send you a message.

Thank you for your reply, I appreciate it. Always continuing to learn, and will consider this more w/ respect to my own experience (not that I haven’t felt like I’ve been trying with a lot of exhausting effort and detailed attention already to figure out what the heck goes on w/ my body and insulin and glucose…! but more info and others’ experiences is always helpful and again, thank you!)


Becky, there is one more called SWAG. Read on.

Years ago, before Tandem’s BIQ & CIQ, when I was on a basic pump and an earlier Dexcom 7sts, I ate supper out three evenings in a row. Same place, same food, after work conference. Calculated carbs entered into pump the same dose when food placed on table and ended up with 3 different outcomes. One high, 1 low, and 1 on target were the results 2-3 hours after the meal.
My wife and I were majorly befuddled and asked our endo’s nurse CDE pump trainer what happened. With restaurants doing portion control, etc, the carbs should have been the same, right? The CDE responded the situation was a SWAG. My wife & I gave her a quizzical look to which she responded, “Scientific Wise Ass Guess”. She further explained there is not explanation.
I hope this helps you see you can do everything right and things will still go haywire.

That’s a great anecdote, thanks. SWAG - was skeptical of this term (a fancy acronym for what dubious “medical” analysis?..) but pleasantly surprised to find out what was meant by it. Yep indeed, SWAG is entirely my experience w/ T1D, having had it almost two years now (not long I know, but long enough you’d think being attentive and observant would count for more than it’s seemed to) and keeping tabs on every single carb, insulin dose, glucose level, and other potential factors. It’s like my body just likes laughing in my face: “Oh you think this is how x and so-and-so works, well, let’s just straighten you out about that…” !

That’s the kind of question I expect from people who have recently changed to a new “protocol” -exercise, diet and behavior and aren’t sure what to do. Never be afraid to ask questions, to question the answers, because no one knows everything about anything.

What to do with fiber depends on whether you are a termite, a cow or a human, so you are better off asking this of a vet than an “medical doctor” or a “nutritionist”.

Unless you consider wood chips and hay as food, you should subtract dietary all fiber from your carb counts. Fiber is either soluble or insoluble in the human gut, but it is always indigestible.
If anybody tells you otherwise, they believe; they do not know.

They do not understand digestion or how to interpret the nonsense on food labels. Fiber is only under carbohydrates because it is not lipid or protein. Fiber should be shown as an inactive ingredient, as is done for medicine and supplements.

If fiber is listed as included under “Total carbs”, subtract all if it. It has no nutritional value for humans.

I don’t care what philosophy a doctor or nutritionist believes in. Those are “medical opinions”, not facts, but based on anecdotes and faith, like a religion.

I make decisions that effect my health based on facts and knowledge. As a human with type 1, if I didn’t subtract fiber from net carbs,no matter what I used as a insulin to carb ratio, I might as well be guessing.

btw, If you don’t look at added sugars as a percentage of the carbs in a meal, the response you get during the first two hours after you eat will be a surprise. If you don’t include enough or include too little fiber, your bathroom visits will too.

If you work to keep your diabetes well managed long enough you will find ways to simplify decisions because its too much work otherwise. You will eat more predictable meals of predictable sizes that include what you like to eat and nothing you don’t. You will condition your gut to expect certain size meals at certain times. That "diet will gradually change and you will become skilled at finding substitutes, one change at a time. You will look at new food and compare them to ones you know. Estimating food content will either become instinctive, or you will have a short list that you can refer to, not an encyclopedia of foods.

I have 4 breakfasts, 4 lunches and 6 dinner that I eat +45 weeks a year. My food diary has meal numbers, each meal has approximately 40 net carbs. I can substitute an ingredient for one of the fixed ones ad have a pretty close estimate of the effect,

If you are forced to eat food whose composition is unknown to you, the best you can do is compare it to things you know and compensate afterwards. When I eat out on vacation I mostly order things I know, with the variations being in fat and protein.