Carb counting question

So I’m trying to learn how to carb count really well and I have a question. I’ve heard mixed things about this so I’m curious what you guys do. Is it true you can subtract the dietary fiber from the carb count when calculating carbs or no? Or is there a certain amount of dietary fiber that has to be there before you do this? Im slightly confused.

@Aparker2012 Ashley, some do, some don’t but what’s more important is that you find out what works for you. Take good notes at first and you will be able to tell if high fiber has anything to do with your blood sugar control. Diabetes is a bit of a science project sometimes. When in doubt use less insulin… you can always take more

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Hi, Ashley,

Joe @joe gave you the basics. To reinforce what he said, it’s how your body responds to carbohydrates and the type of fiber in the food.

Here’s the short version of what I do. I look at the carb count on the package/restaurant nutrition information and calculate based on that. That’s an easy place to start. Don’t try to get too “technical” as you’re getting started.

Over time you will begin to recognize which foods lead to a quick glucose rise (e.g., potato chips) and which ones are “slower” (e.g., brown rice). You’ll also recognize which ones have a greater carbohydrate load per volume (e.g., white rice).

It’s not quite “trigonometry or calculus.” It’s more like “algebra.” But start with simple “ratios” and build from there (e.g., 1 unit per 30 grams; this is my “ratio” - yours may be different).

Good luck to you!


Hi Ashley @Aparker2012, what both Bill and Joe wrote also applies to me it is how different foods affect MY body. And as Bill suggests, don’t try to get too technical.

Through trial and error you will see how much insulin your body needs for many of your favorite foods in the serving size you prefer to eat. When looking at “new” foods that you want to try I suggest that you look at the “Total Carb.” on the label and apply your calculated I:C ratio and go from there. You will note on the current FDA label there are two “fiber” listings; “Dietary fiber” and “Insoluble Fiber” - insoluble could almost always be deducted but I only deduct for one half of dietary fiber if the amount is “excessively large”. Bill, Joe and I [and several other members here] all grew up with diabetes and have done well before “carb counting” became the rave - we played the game from instinct and learned from our mistakes.

Yeah, all different. As in a post above, some have different responses to potatoes vs rice. For me, I need much less than expected insulin for any potato dish, exactly as expected for rice and more than expected for an orange. I keep a food diary which helps a lot

My trainer told me to deduct half of the fiber from the total carbs. This seems to work well for me.


The “fiber deduction” rule of thumb is, you can subtract the fiber count from the carbohydrate count, when there are >4grams of fiber in the food. (Example: Carbohydrate: 35 grams, Fiber: 6 grams. Your carb count is 29 grams)

I am 71 and only 2 years a T1D so I am still learning. However, i had the same question early on which i posed to a lady in her late 70’s who had been T1D since about 15. Her reply was 'No, I do not deduct" and so i do not and it does appear to have worked for me

I was always taught that you subtract the fiber if it is over 5 grams and also sugar alcohol should be divided by 2 and then that amount taken off the carbs regardless the amount of sugar alcohol. So, say you have 10g of sugar alcohol you divide by 2 and take that amount off. In this case you would take 5 carbs off whatever it is that has the sugar alcohol. I was taught by my pediatric endo and dietician as well! Hope this helps!

I’ll havs to try a few of these out and see what works best for me! Thank you guys!