Net Effective Carbs?

Can someone explain or point me to a resource that explains the thought process behind measuring net effective carbs? So far nothing I've ready about it makes any sense to me. I've sorta developed the attitude that it's woo. But if there is info out there that validates the theory, I'd love to read it.


  • Though I don't personnally really follow it, read the Atkins book. If nothing else, if gives good definitions, reasons, and the science behind low carb and what net carbs are and why they are important. This will give you a good starting point for a reference that you are looking for. Let me know if I can help with anything.
  • sb4480
    sb4480 Posts: 203 Member
    I believe the reason why you're told to subtract the fiber from the carbs is because while all fiber contains carbs, your body can't/doesn't process it the same way. Most of it just goes right through your system, that's why you're told to eat more fiber when you're constipated. So even though you have those added carbs, your body isn't using them for fuel.

    I don't understand the sugar alcohol connection in net carbs, but I avoid SA at all costs.
  • kiramaniac
    kiramaniac Posts: 800 Member
    (There was a thread over on the Keto page too on this - I've posted this in both locations)

    A nice article on this...

    And from the Atkins product site -
    When you follow the Atkins Nutrition Approach, you actually count Net Carbs, which means the total carbohydrate content of the food minus the fiber content. The Net Carb number reflects the grams of carbohydrate that significantly impact your blood sugar level. These are the only carbs you need to count when you do Atkins. Foods that are low in Net Carbs are foods like nutrient-dense vegetables and fruits that don’t have a significant impact on blood sugar and therefore don’t cause you to gain weight. Sometimes we call these foods “good carbs.”

    You can calculate the approximate Net Carbs yourself by looking at the information provided on a food label (grams of total carbohydrates minus grams of fiber). For foods that don’t have a label, like fruits and vegetables, you can use the Atkins Carb Counter.

    Atkins science allows us to calculate Net Carbs in our products more accurately. In addition to subtracting grams of dietary fiber from total carbohydrates, we’re able to account for glycerin and other ingredients that have minimal impact on blood sugar levels that might not show up on a standard food label. We can also check Net Carbs using analytical techniques. But what is important for you to know is that all Atkins bars and shakes are low in Net Carbs.

    I think subtracting fiber is mostly valid. But there are some questionable products out there (I'm talking about you, low carb tortillas) where things often don't add up. I really question having 30 grams of carbs with 28 grams of fiber. My suspicion is that they are adding sources of fiber to the ingredients, and counting it in the fiber count without counting it in the carb count. I have no data to back this up. It just seems off to me. (Low Carb Tortillas are a YMMV thing -- if you have a stall, they are the first thing you should be cutting).

    The second class that you typically subtract is sugar alcohols. However, sugar alcohols are a broad class of items - a number of which DO have impact on your blood sugar. In my opinion, erythritol is one that is OK to completely subtract - glycemic index is zero. Malitol is a horrid product that has a relatively high glycemic index. If it's malitol in your product (and now I'm talking to you, Atkins bars) you should count some of those sugar alcohols in your carb count. I think a lot of people count half the Sugar Alcohols. Atkins Bars are another YMMV item - be cautious about eating these too regularly. And if you eat too many, you will pay. That malitol will make itself known (be near a bathroom).

    Mark's Daily Apple had a good article on some of the different sugar alcohols --

    I think to have a rational discussion of sugar alcohols, you really have to be looking at each one individually - because they are all quite different. Erythritol is amazing; Malitol is evil. I've made desserts with Z Sweet (a blend of erythritol and stevia) that you cannot tell was not made from sugar.
  • JaceyMarieS
    JaceyMarieS Posts: 719 Member
    ^^ All of this! I've had both successes and failures with net carbs

    Things that I make myself - muffins in a minute, seed-real - seem to be safe. Almond flour, coconut flour, chia and flax meal are all naturally high in fiber and thus low net carb and I've used my glucometer to make sure they are safe for me.

    Things that I purchase - Quest bars, Atkins bars, low-carb tortillas, etc, etc - are a crap shoot. Some affect my blood sugar detrimentally while others don't.

    So, i consider net carbs valid if I'm creating my own recipe and proceed with caution on anything in a package with multiple ingredients.