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What “They” Don’t Want You to Know About “Net Carbs”

What “They” Don’t Want You to Know About “Net Carbs”

Unfortunately, “net carbs” aren’t everything they’re cracked up to be. Here’s why.








These days, just about every drug, supplement, grocery, and department store sells tasty protein snacks claiming that large portions of their carbohydrates don’t “count.”

While one of these bars might list 25 grams of carbohydrate on the nutrition facts panel (which the FDA regulates), the packaging copy (which it doesn’t) offers the friendly reminder that only a few grams of these are “net” or “impact” carbs.

This marketing ploy has been around for a while (Atkins might have started it?), but it’s in the limelight again due to the popularity of the Quest Bar, which is now the subject of a class-action lawsuit (and which I actually like and recommend as a product, despite the misleading marketing).

What’s the real story of the “net carb” and its cousins, “impact” and “active?” Let’s find out.

The Curious Case of the Disappearing Carbs

We know the sales pitch–eat a delicious, high-protein bars or other type of treats that “cost” only a few of our precious daily carbs–but how does this work, exactly?

What is a net carb and what are the rest? Where do they “disappear” to in our bodies if they aren’t metabolized normally?

Well, these questions lead us to the first problem: these “special” types of carbs have no legal definition and the FDA doesn’t evaluate any claims using them.

What most manufacturers do to calculate them, however, is take the total number of carbohydrates a product contains and subtract fiber and sugar alcohols like sorbitol, maltitol, and xylitol, and list the difference as the “net,” “active,” or “impact” number.

The reason often given for this “adjustment” is that these types of carbohydrates don’t impact blood sugar levels like other types of sugars and thus “don’t count.”

While there’s some truth in this–fiber and certain sugar alcohols like xylitol and erythritol have little effect on blood sugar levels–what most people don’t know is they still contain calories.

That is, the majority of these “invisible” carbohydrates are metabolized by the body and do count to your daily calorie intake

For example, only insoluble fiber can’t be processed by your body and goes right through you. Soluble fiber turns into a fatty acid in the gut and contains somewhere between 2 and 4 calories per gram (scientists aren’t sure yet).

If you knew how many grams of insoluble fiber were in these products, you could subtract them from the carbs that “count,” but it wouldn’t be more than a few grams at most.

This also applies to your meal planning. If you really wanted to, you could sit down and work out how many grams of insoluble fiber you’re eating every day and subtract that number from your daily carbohydrate intake, but in my opinion it’s not worth the trouble to find out that you can take a few extra bites of food every day.

Like soluble fiber, sugar alcohols contain calories as well, ranging from the 4.3 calories per gram of glycerol (more than sucrose, ironically) to the 0.2 calories per gram of erythritol.

(As an aside, if you want a truly 0-calorie natural sweetener that also comes with some nice health benefits, check out stevia.)

So, all this is why I often hear from people baffled as to why they’re not losing weight despite following their “macros” perfectly, only to find a handful of improperly-accounted-for “net carb” products lurking in their meal plans.

The bottom line is you can eat these foods if you’d like but I recommend you count all the carbs listed on the nutrition facts panel and ignore the marketing buzzwords.


What are your thoughts on net carbs, impact carbs, and the like? Have anything else to share? Let me know in the comments below!











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Leave a Comment!
  • Jay

    Well, that was a fast response,) Thx for the article, it clears up the confusion nicely!

    • Michael Matthews

      Thanks! 🙂

  • Jessica

    Thanks for posting this article! Its very helpful and I completely agree with you!

    • Michael Matthews


  • Anthony

    Great article, but I’m left unsure of how to determine the calories of a product like quest bars since the macros don’t add up to the listed total calories. If you subtract protein and fat’s calories from total calories of the cookies n cream bar…180-(21×4)-(7×9)…you’re left with 33 calories, so ÷ by 4 and you’re left with 8g carbs, somewhere in the middle of the net and actual carbs? Any idea why the total calories and macro’s calories aren’t equal? Thanks.


    • Mike Rossi

      7f x 9 = 63cal
      21p x 4 = 84cal
      22c x 4 = 88cal
      Actual calories = 235
      Quest then subtract 17g fiber x 4 = 63 calories so they can claim 180cal on the label, even tho this is clearly flawed.

      • Serge

        I guess I should check carefully all the labels for the food I use. I use a MyFitnessPal to count calories and didn’t realize that some manufactures lower amount of calories.

        • Michael Matthews

          Yeah that’s one of the reasons I generally stick to foods I prepare myself.

      • Anthony

        Yeah that was my concern….if I wanted to eat a quest bar, would I have to calculate the total calories myself by multiplying macros? (Essentially disregarding the company’s claimed total calories)

      • Michael Matthews

        This is correct.

  • Elt31987

    Excellent article. This has explained a lot. While i always counted EVERY carb in these bars regardless atleast i know now about the net carb claim. Thanks again Mike

    • Michael Matthews

      Thanks. Yup that’s how to do it. Gonna have to calculate the calories yourself too.

  • Pedro

    Cool article Mike. So, that said we would have to add those calories to every Quest Bar and they are lying about those 170 calories, 190 and 210 they are putting on the label. Right?

    • Michael Matthews

      Yeah that’s right. There are more cals and they are claiming.

      • Chris Parsons

        Interesting. I just did the math on a QuestBar I had sitting here. The macro’s are 8g fat / 22g carb / 20g protein, total calories listed 200. But adding up the macro’s I get 240 kcal. To reach the 200 kcal number you have to plug in 12g of carbs, I presume the rest are the isomalto-oligosaccharides which they aren’t counting.

        • Michael Matthews

          Exactly. The cals are going to be a bit lower though because I soluble fiber doesn’t have the full 4 cals per gram like other carbs.

  • Pedro

    Never mind. I just realized you already answer these questions. I always tracked my quest bars with the net carbs but from now I’ll put the total carbs. Anyway I track macros not calories.

    • Michael Matthews

      Same here.

  • Jim Easton

    I am diabetic & the Quest Alll Natural (Erythritol) bars cause a rapid spike in my blood sugar. Not so with their sucralose sweetened bars.

  • Mike

    Something like this combined and/or another mistake could slow fat loss progress..lets say its 50 cals off on the package and you eat one per day..that’s 350 cals in a week ..calculate something else wrong and all else going on and you could dip into your deficit for a few days..shame on Quest and these companies

    • Mike

      The 160 calorie double choc chunk bar is actually 234 calories..still everyone’s favorite now? What a scam

    • Michael Matthews

      100% correct. I see “IIFYM” types loading up on these bars thinking they’re only a few grams of carbs per.

      • Mike

        The fact is they wouldn’t sell as many if the labels were correct. People are already hooked now and are defending the labels fiercely saying that its all “talk”. Amazing how people trust these companies. Just hate seeing people spin their wheels.

        • Michael Matthews


  • Anthony Jesse

    Truvia sweetener says it has 3 carbs per serving yet has 0 cals. It’s representative claims the body doesn’t process the sugars which is why it’s 0 cals. Any truth to that?

    • Michael Matthews

      Yeah those carbs come from erythritol, which contains about 0.2 cals per gram.

      • Anthony Jesse

        Thanks for responding. I think that it’s great that you take the time to answer e-mail.

        • Michael Matthews

          My pleasure 🙂

  • April

    Great Article! Now I know why my weight loss has stalled, too many “not so” low carb items. I use Joseph’s pitas a lot and lavash bread as well as dream fields pasta and mission low carb tortillas as substitutes for stuff but I guess they’re not as good as I thought lol. Thanks for the info yet again 🙂

    • Michael Matthews

      Thanks! Yeah watch out for “trick” foods like that!

  • Jacob

    Hey mike. So what about products that are high fiber low carb and do state the fiber contained is all insoluble (like fiber one, flat out wraps, and la tortilla factory high fiber tortillas) are the calories on there label true? Or should we do the math ourselves and calculate calories based off there given macros (including fiber carbs into the calories) I eat a lot of fiber a day (80-100g) so this can lead to a big difference for me. Thanks for the response!

    • Michael Matthews

      You can trust the cals but IMO just count all the carbs. Only insoluble aren’t digested by the body but is it really worth paying attention to this just so you can eat a few more bites or some other carb?

      Hmm that’s too much fiber. Check this out:


      • Jacob

        Hey thanks, still kinda confused tho, so quest macros and fiber one macros (by macros I mean calories) are correct? Like a choc brownie quest bar says 170 cals, and fiber one bran says 60, that is correct??? And what do you mean when you say just count all carbs (I love high volume low cal foods) so this ca be a big difference daily thanks!!!!

  • Pingback: Detecting Impostor Foods: What to do when Macros and Calories Don’t Add Up - Calorie Counting Made Easy()

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  • Theodore Boosalis

    Great article Mike. I would say in my personal case, I never eat those bars – I eat whole foods – the kind of food that makes fat storing the hardest – non-starchy veggies, berries, and I time my banana eating to pre-workout meals only. So net carbs made a huge difference in my life – and I would say that even though soluble fiber is digestible – I think it’s the idea that some of the fiber is not – and therefore really cannot be computed into a daily calorie goal – this worked wonders for me – lost 53#+ fat pounds with blood work to validate my results from last month. Jury is still out on this topic – please don’t dismiss the idea of net carbs – this is important. Plus, the HC-LF Western Diet is, to me anyway, a huge failure. Leads to diabetes. I corrected my condition by eating a high protein, high fat, low carb diet and it worked.

  • Coffeeforever

    If someone were eating an average of 2 quest bars a day for the last year and were fitting them into their macros according to the calories listed on the package, should they now recount their current calorie intake during or before starting a reverse diet?Its a little bit of a mind $%@# for someone who’s been calculating their intake !

  • Bodies Evolved

    Thank you so much for this! I’ve tried to explain this to many of my fitness and nutrition clients, but people seem to cling to that net carb thing. It’s understandable, because it lets them believe they’re still meeting their macros. I will be sending them this link!

    On Quest bars specifically, I contacted the company directly about their faulty calorie calculations listed on packaging about a year ago. They replied with a lengthy BS explanation about net carbs. I was in contest prep at the time, and anyone who’s monitored carbs as closely as contest prep typically requires knows that every carb really counts, and the “net carb” thing is mostly marketing propaganda.

    After their reply, I quit eating Quest bars just on principle. The more honest thing would be to label according to standard conventions – i.e. a carb is a carb, regardless of type. Especially for those less versed in the calorie value of macros, for those beginners making an effort to change their lives, don’t play games with their minds. Give them straight calorie and carb data so they have a fighting chance. That minority who wants to work the net carbs thing can do their calculations and adjust down, but I believe the majority of us would rather just have the straightforward data!

  • gaetano simonelli

    Is this why the new quest bars now have more fat as well as more calories ? As well as switching to soluble corn fiber instead of IMO

  • Harry Ashton-Potter

    In UK/EU I’m pretty sure the labels on the back list the net carbs, instead of total carbs. for these almonds, the fibre is higher than “net” carbs. If you add the macros up (with fibre as 2 calories per gram) then it matches the total calories.


  • Laynie Wolfe

    I lost 50 pounds eating multiple questbars a day with practically no exercise whatsoever. (Which wasn’t ideal, but I was in college. I’m much more active now). I 100% love questbars and believe in them with my whole heart haha. What I don’t understand from your article is why “net carbs” aren’t a real thing….are you saying that they aren’t giving accurate calories on the questbar packaging because they are only counting the net carbs towards the calories? In that case, if that is true, then I see the point you’re making. But if you at just saying that a carb is a carb and subtracting the fiber doesn’t make a difference, then I don’t understand. Because there is a real difference between soluble and insoluble carbs….right? One is absorbed by the body, and one isn’t. In that case why would you NOT subtract the fiber?

    • Quoted from above:
      “If you really wanted to, you could sit down and work out how many grams of insoluble fiber you’re eating every day and subtract that number from your daily carbohydrate intake, but in my opinion it’s not worth the trouble to find out that you can take a few extra bites of food every day.”

      • Laynie Wolfe

        Right, but in bars, such as questbars, that have anywhere from 14-18 grams of fiber, and eating multiple of them a day….that’s a whole lot of carbs you could still eat. That’s not a “few extra bites”. And, if you’re serious and strict about counting macros, numbers like that for sure matter. That’s why I wanted to make sure I understand what is being said in the article. Do insoluble carbs count, or not?! Haha

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