Most people with diabetes must rely on counting carbohydrates when they eat food to help manage their blood sugar levels.
But that can become trickier when food labels sometimes differentiate between “total carbohydrates” and “net carbohydrates”.
What is the difference between these two types of carbohydrates and which one should you use for your diabetes management?
This article will explain what total carbohydrates are, what net carbohydrates are, and how to determine when to use each number.
Why is carbohydrate counting important?
At the molecular level, carbohydrates are broken down into glucose in the bloodstream that only insulin can break down and help the body’s cells to digest.
If you live with insulin-dependent diabetes, counting carbohydrates will therefore help inform your insulin dosage decisions.
If you live with non-insulin-dependent diabetes, you may count carbohydrates to better calibrate oral diabetes medication like Metformin, or even exercise, to help manage blood sugar levels.
Since people with diabetes either struggle to make enough insulin naturally or their bodies make no insulin at all, making sure one is aware of the number of carbohydrates in a food that’s consumed is vital to good health and wellbeing.
What are total carbohydrates?
Total carbohydrates tell you the absolute total number of carbohydrates a serving size of a given food has.
If you live with diabetes, this also nominally tells you how your blood sugar will be affected by a certain food. The “total” means that the number is comprised of four things:
- Total sugar – This is the total grams of naturally occurring sugars that are found in the serving size of a given food
- Added sugar – This is the total grams of artificially added sugar that are added during the processing of a certain food (like dextrose or sucrose). Also commonly found here would be grams of sugar from table sugar, honey, or agave nectar
- Dietary fiber – Total grams of fiber that cannot be broken down easily by the GI tract of a human being
- Sugar alcohols – Total grams of sugar alcohols. These are a type of sugar (polyol) with a slightly different chemical makeup than added sugar, resembling both sugar and alcohol. They have minimal effects on blood sugars and are commonly added to food to give them a sweeter taste, without the added carbohydrates and calories. Examples of sugar alcohol include: xylitol, sorbitol, maltitol, and erythritol
Together, these four numbers comprise the total number of carbohydrates in a given serving size of a food.
While this is an extremely helpful way to figure out how a food will affect your blood sugar, it doesn’t tell the whole story.
What are net carbohydrates?
Net carbohydrates represent the total number of carbohydrates that will actually affect blood sugar levels. Sometimes they are called “digestible” or even “impact” carbs.
While there is no official definition of the term “net carbohydrate”, for people who are either eating a low-carbohydrate diet or for whom counting carbohydrates is extremely important (i.e. people with diabetes), it is important to know how to calculate this.
Since naturally occurring fiber isn’t broken down in the small intestine, the carbohydrates that accompany this macronutrient do not affect blood sugar levels.
Additionally, subtracting sugar alcohols from a food (typically they only exist in processed foods) helps give you the net carbohydrates as well, since they are also not digested in the same way a typical serving of sugar is.
Studies show that sugar alcohols don’t seem to have a major impact on blood sugar levels, but people’s individual responses can vary. This is why sugar alcohols are commonly added to “sugar-free” candies, ice cream, and bubble gum, although they can cause bloating and GI discomfort.
Sugar alcohols seem to only be absorbed into the bloodstream briefly, and then exit the body through urine, making their impact on blood sugars minimal.
How do you calculate net carbohydrates?
To calculate net carbohydrates, one would take the total number of carbohydrates and subtract both the total number of grams of fiber and the number of grams of sugar alcohol.
However, since sugar alcohols can affect blood sugar minimally, and everyone digests sugar alcohol differently, some people may prefer to subtract only half the number of sugar alcohols for net carbohydrates.
Net Carb = Total Carbs – Fiber – Sugar Alcohols (or 50% of sugar alcohols)
The resulting number is the net number of carbohydrates in a serving of food, and for optimal blood sugar management, one would count that as the number to base insulin and/or oral diabetes medication on.
Mindy Nichols, RD, CDE says, “Net carbs are only estimations, as everyone’s digestive systems and bodily processes are different. Working with your doctor, experiment and see what works best for you!”
It’s important to note that if you live in some countries outside of the United States, the “total carbohydrate” number already has the total grams of fiber subtracted out, so there is no need to do the equation.
Pros and cons of counting net carbohydrates
Counting net carbohydrates is an excellent way to fine-tune your diabetes management, but it might not be for everyone. Here are some pros and cons of approaching this way of eating:
Pros
- Eating this way promotes whole, unprocessed foods
- It incentivizes eating more fiber
- Decreases risk for hypoglycemia
- It’s a less restrictive way of eating (can promote eating more fruit and other higher carbohydrate whole foods due to their high fiber content)
Cons
- May not be suitable for everyone’s eating plan or diabetes medication regimen
- Can result in eating lots of “sugar-free” candies and treats that aren’t as healthy (if the focus is only increasing the number of sugar alcohols and not fiber)
- Isn’t always 100% accurate for dosing
- Food labels aren’t always available (for instance at family or friend’s homes, and when out at a restaurant)
Lauren Plunkett, RDN, CDCES, author of Type One Determination, encourages people with diabetes to increase their intake of fiber-rich foods to enhance insulin sensitivity, lower inflammation, and promote the microbiome for a healthy body and mind.
“Everyone digests and absorbs food differently. This can depend on age, the environment inside the gut, and activity level. No two stomachs are alike! Since we are unique digesters, it’s important to determine which food sources of fiber are most compatible with our system and blood sugar goals, whether or not we choose to subtract fiber grams from total carbohydrates.”
Conclusion
Knowing both the total number of carbohydrates and the net number of carbohydrates in a food you’re eating is important, especially if you live with diabetes.
Calculating the net carbohydrates of a food can fine-tune both your medication dosages as well as your diabetes management, resulting in better blood sugar levels, lower hba1c levels, and an improvement in quality of life.
However, eating for diabetes is not a one-size-fits-all endeavor, and everyone’s experiences may vary.
Always talk with your doctor before making any changes to your eating and/or medication management plan.
Yvonne McMullen
Hi! I am 59 and have recently been diagnosed as type 2 diabetes. I am in the beginning stages and haven’t even begun medication yet. My total sugar level was 293 with an A1C of 11. I have never had to manage this. I understand the concept of carbs vs. net carbs and have no issue with figuring this out and whole foods, etc. I don’t really eat processed foods, so that is a good thing. But my question is: What number to I shoot for at each meal? How many net carbs is too much? I have eliminated anything white in my diet. Minimal breads (which consist of Ezekiel), black rice, sweet potatoes (occasionally), etc. So, what do I shoot for? I know it’s a general question, but this is where I am a bit lost. Also, snacking after dinner? Yay/Nay? I like to eat a mini bag of Skinny Pop after dinner. OK or not?
Christel Oerum
A diabetes diagnosis can be overwhelming and I know there’s a lot to learn, but keep learning and it will get easier. A set Diabetic Diet doesn’t exist so you’ll have to learn what works for you. A good way to start is by measuring your blood sugar before a meal and then again 1.5-2 hours after. If your blood sugar is elevated 1.5-2 hours after your meal, compared to your blood sugar prior to eating, the number of carbs might be too much for you or your body can’t tolerate the type of carb. So you can try and cut down on the amount of carbs or substitute them for something else.
Also, remember that there are carbs in most foods, so look at the nutrition labels or look them up online.
I think this article would be a good next read for you, it has more details on what blood sugar levels to aim for: https://diabetesstrong.com/what-are-normal-blood-sugar-levels/
Federico Macias
I AM TYPE2 since 2-04-2021, I am 65 years old, I take Metformin 500MG @supper 3PM. My sugar level has been great the past three months, 91-117. On 7-22-2021 @ 8PM I tested @93, I continued fasting, @6AM 7-23-2021, I tested @102. Did I have a pizza in my dream. Please educate me. THANK YOU!
Christel Oerum
I would consider 93-102 mg/dL very stable blood sugars. However, it’s also possible that one of your readings was slightly off (there is some variability in blood sugar readings). But a lot of other things impact your blood sugars aside from food, so even if you’re fasting you can see your blood sugars go up. The main things impacting blood sugars outside food are your hormone changes throughout the day (Dawn Phenomenon is very normal), others can be stress, hydration, illness, and the list goes on.
But an increase of 9 mg/dL is nothing to be concerned about
Erin Wojciechoski
Hi, I’ve been a type 1 diabetic for 33 years and am still old school with insulin shots (no pump). I am thinking of trying out the Keto diet and would love your opinion on it from one diabetic to another.
Christel Oerum
You can do keto if you want to (more on keto HERE). I personally didn’t like it but that doesn’t mean that you won’t. I wasn’t tracking my calories, so ended up over-eating and gaining weight, fat calories are the most calorie-dense and if you have a good appetite easy to over-eat on. I also found my blood sugars to be very hard to manage and I ended up coasting high most of the time, again due to the fat. But some people love it
Peggy Konold
I tried it and in 3 months gained 7 pounds. I do not think a diabetic can process the fat so you pack on the pounds. It just didn’t work for me.
Heman H Lee
According to Dr, Berstein and newer research on protein metabolism, you need to factor that in as well
Christel Oerum
I agree that protein and fats need to be part of the calculation when you determine your insulin dose. However, that was not the focus of this article why it’ not outlined. You might enjoy this article instead https://diabetesstrong.com/count-calories-not-just-carbs/
Barbara A Ely
I am a 65 yo woman who is now 3 years cancer free from Stage 4 mantle cell lymphoma. About 5 months ago I had a sudden and unexpected high blood sugar spike … like 425 high. Dr. put me on metformin and rybelsus … both low dose. I talked to the hospital dietitian and went to Pinterest and printed like 500 KETO recipes … took every single bad thing in my home OUT … gave it all away … restocked with KETO items. My carb limit is set at 45 max per meal. I average around 30. Within 5 weeks I lost around 15 pounds and was off both of the medications. I LOVE THIS NEW LIFE STYLE! There are so many new and great products out there … and it seems like no matter what recipe you like … you can find a KETO version. Talk to your doctor and see what they think. Even my cardiologist is taken aback … my labs last week were all in the “excellent” range … first time since AFib hit me in 2007.
Shauna
Erin me too even counting carbs for me is sometimes hit and miss but I reallllly wanna try a loop insulin pump – don’t you?
David Holmes
Hi Christel, have you tested Quest bars since they moved away from IMO (isomalto-oligosaccharides)? That is definitely digestible. The newer bars using soluble corn fiber should have less impact on blood glucose.
Christel Oerum
It has been a while since I had one, but great point
Suzy McKinnon
Thanks for all your tips, especially carbs. I’m on a pump and exercise 6 days a week now. I do get frustrated sometimes with setting my pump before exercise. My dr has me setting it at 55% an hr before. That works most of the time, but my exercise regimine is swimming 1 day, ab attack 2 days, body vive 2 days, and yoga 1 day. I’m finding that the 55% before doesn’t always work. So now I’m changing it for swimming and yoga because they are in the morning, so I eat my breakfast an hr before and enter the carbs at 80%. I sure wish it wasn’t so difficult to get things right. Any advice would be appreciated.
Christel Oerum
Hi Suzy – I’m glad you like my tips & tricks.
I’m not surprised that the 55% doesn’t work for all of you different activities since each will impact your sugars differently, but it’s a good starting point. My suggestion would be to keep the meals/workouts and timing for them the same for a few days and take detailed notes. That way you can find your formula for each type of exercise + time a day.
The complexity can be frustrating, believe me I get it. But good news is that when you find those formulas life becomes so much easier. They most likely won’t last you a lifetime (our sensitivities change) but it’s always easier to make tweaks than to start over.
Good luck – I know you will figure it out
Robbie Harris
Hi I’m wanting to help my granddaughter with carb counting for her diabetes., she wears s Pump and is so good at doing all this herself she’s 8 but I’ve never been to help or learn the new way with carb counting .. her mother had always done it.. I guess she was afraid to count on others I get it completely but now she needs help with sophee diabetic routine ., my question is how do I find the carbs for the food and how do I convert
Christel Oerum
I’d recommend getting a kitchen scale and start weighing out the food that she eats. You can start with carbohydrates, but remember other food will often have carbohydrates as well (for example dairy). You can then either google the carb count or look it up in an app such as MyFitnessPal or LooseIt. If you prefer to look it up in a booklet I remember CalorieKing had a pretty comprehensive booklet, you might be able to get that at your granddaughter’s doctors office.
And please know that it will take some time to figure it all out. Be patient with yourself, you’re doing a great thing