How to calculate net carbs for Keto? (the easy way for beginners)
The equation for how to calculate net carbs or digestible carbs is pretty straightforward. Inside this article, Mr Skinny Pants will show you exactly how to read a label to determine the total and net carbs of a particular food. Later, we will also cover the problems associated with relying on net carbs vs total carbs.
Let’s start by looking at and reading a nutrition label:
There are 2 things to pay attention to here:
- Total Carbohydrate
- Dietary Fiber
Frist, we don’t need to pay attention to Total Sugars, Added Sugars or Sugar Alcohols.
Those will discuss them later but we don’t need them to determine net carbs.
Second, to determine the net carb content of our food, we will subtract 2. Dietary Fiber from 1. Total Carbohydrate
The basic net carb equation will look like this:
Total Carbs – Fiber = Net Carbs
As you can see from our example label above it would be 37g total carbs, minus 4g of dietary fiber equalling 33g of net carbs. Way too much for a successful keto dieter!
This is the easiest & most reliable way to calculate net carbs!
We have lots of ground to cover when talking net carbs and low carb foods. Let’s begin a chat about counting net carbs vs total carbs for just a bit. Deal?
Should I count net carbs or total carbs?
In this section we will talk about counting net carbs vs total carbs. If you track total carbs, you’ll be including all the different types of carbs in your food like starches, dietary fiber and sugars. Running a calculation for net carbs will tell you only the carbs your body can easily turn into glucose by does not dive into the subtitles of non digestible carbs.
As you’ll see, precise equation for net carbs is actually more difficult but don’t worry we will get to it later in this article.
An easy way to think about this is…
BEGINNERS should track TOTAL Carbs
ADVANCED keto dieters can count NET Carbs
You might be thinking “Why is that Mr Skinny Pants?”
Glad you asked!
Counting net carbs is risky because your total carb intake and especially sugars, can climb too high without a precise calculation.
Food manufactures make labels difficult to understand, as you’ll see in “how to calculate net carbs advanced” section at the end of this article.
Getting carb count wrong can cause spikes in your blood sugar which can stall your progress. If you’re new to keto, Mr Skinny Pants recommends keeping your total carbs calculated to under 30g per day or even under 20g if you can manage it.
What are the Pros and Cons of Counting Net Carbs
Now, let’s quickly chat about the pros and cons of using net carbs as our guide on a keto diet:
Net Carb Advantages
- It’s less restrictive: It’s easier to stay under the 20-30g magic number when using net carbs. You’ll be able to consume a wider range of foods.
- Higher fiber intake: Eating foods higher in fiber helps digestion, decreases blood sugar spikes and is overall healthier.
Net Carb Disadvantages
- It’s not easy to be 100% accurate: The true equation to determine net carbs when dealing with processed foods, sugar alcohols and the responses of our individual bodies is actually very difficult.
- Leads to carb creep: Carb creep is where we are ‘tricked’ into thinking our carb content is low enough because we miss sugars and other things hidden in the basic net carb equation. This can stall our progress if we’re trying to lose weight.
- Tougher for diabetics: Counting total carbs is a more fool proof way of dealing with blood sugar issues for diabetics.
How to calculate total carbs?
Let’s talk about total carbs for a minute. Total Carbohydrate is actually an official term from the FDA (food and drug administration) while the term net carbs came about a decade ago when companies tried to lower the carb content of their foods. The term total carbs will include dietary fiber, total sugars, added sugars and sugar alcohols.
The FDA’s requirements for nutrition labels make it a cinch to figure out:
If you are new to the keto diet you should track total carbs or use our the net carb calculation for beginners above for a fool proof path to success!
Before we dig into some advanced equations for net carbs, lets backup and answer an important question.
What are Carbs anyways?
The primary role of carbs (starches & sugars) is to provide energy to the body. Carbohydrates are one of three macronutrients. (fats and proteins being the two)
Carbs we eat are broken down into glucose (blood sugar) before they enter the bloodstream. Glucose is taken by the body through a series of complex processes to power a number of metabolic tasks in our bodies.
When carbs are not available for your body to process, your body will rely on fats. This is a good thing for people trying to lose weight.
In a pinch your body will convert protein into glucose if it does not have carbs or fats to look to first. Note: This is why too much protein and not enough fat can trip up a beginner keto dieter.
The problem with carbs is that they can easily trigger and increase in blood sugar above what we need.
You might recognize this vicious cycle:
High blood sugar levels tell your body to release insulin.
Insulin helps glucose enter the cells of your body and fuel your daily activities.
Extra glucose is stored in your liver, muscles and cells but if your body does not use the precise amount of glucose (by getting enough physical activity) it will be stored as fat. As you can imagine that’s not what we want to have happen.
As you’ll see, a low carb or keto diet is designed to handle this issue!
Why does Mr Skinny Pants like low carb?
The keto diet forces your body to burn fat instead of glucose through a process called ketosis. This prevents your body from having to rely on carbs for energy. Your body will break down fat into something called ketones promoting fat loss and potentially improving a host of neurological disorders too.
Ok, so I did promise to tell you about the advanced equation to calculate net carbs. Here you go!
How to calculate net carbs? (advanced keto dieters)
Earlier ole’ Mr Skinny Pants promised a more advanced equation to sort out net carbs.
Hopefully you already understand the basic equation for how to determine net carbohydrates.
Dietary fiber can be subtracted from total carbs which gets you your net carbs.
The BASIC net carb equation
Total Carbs – Fiber = Net Carbs
That’s easy stuff right? The advanced equation is much trickier! That’s why we reserve it for advanced keto dieters.
The ADVANCED net carb equation
Total Carbs – Fiber (or 1/2 the carbs from IMO) – 1/2 the carbs from Sugar Alcohols (other than erythritol)
= Net Carbs
This is a slightly simpler advanced equation (removing the exceptions)
As you can see there are a couple other pesky things we need to consider in our advanced approach to how we calculate our net carbs.
The first is one is Sugar Alcohols and the second one is (IMO) Isomaltooligosaccharide (IMO)
What are Sugar Alcohols?
Sugar alcohols have been popular alternatives to sugar. They are sweet and have been touted as healthier replacements to sugar. Since they are not absorbed as easily by your body they need to be considered differently than regular sugar.
Different types of Sugar Alcohols:
- xylitol
- erythritol (this has an exception when calculating net carbs – read below)
- sorbitol
- maltitol
- mannitol
- isomalt
- lactitol
- glycerin
Sugar alcohols are not absorbed as readily by our bodies so we will subtract 1/2 of the carbs from sugar alcohols.
Keep track of this list as it will be important later!
No good rule would be complete without an exception right?
Erythritol exception: Erythritol has zero net carbs! We can subtract the full amount of carbs from erythritol in our net carb equation for keto.
TAKE ACTION> Download a list of SUGAR ALCOHOLS
What is IMO (Isomaltooligosaccharide)
IMO is high-maltose syrup made up of a mixture of short-chain carbohydrates. It’s found in a few foods naturally but it’s most prominently marketed in protein bars as a zero calorie fiber. IMO is pretty controversial as to whether it’s really a fiber or not but either way we need to consider IMO differently in our advanced net carb equation.
If IMO is on our ingredient list we will subtract 1/2 the fiber carbs from IMO (Isomaltooligosaccharide)
The good news is IMO is not super common so it
How to determine Net Carbs (advanced equation)
Let’s use the Atkins Meal Bar (chocolate peanut butter to be exact)
The packaging says it has “3g Net Carbs”
Let’s apply what we know and dig deeper into this net carb thing with our new knowledge!
Here is the actual label with the things we need to consider to find the REAL net carbs.
We see that Total Carbohydrates is 23g, Dietary Fiber is 12g.
Our basic (and safer) net carb equation would tell us that the net carbs would be 11g and we would probably determine that’s too high for our keto diet.
However this label tells us that it has only 3g of net carbs.
What gives?
Atkins wants us to subtract ALL 8g of the sugar alcohol glycerin from our Total Carbs.
Total Carbs (23g) – Fiber (12g) – Glycerin (8g) = 3g of net carbs
Not so fast!
American Diabetes Journal (and Mr Skinny Pants) tells us to think about the sugar alcohol glycerin differently.
We’ve learned that we only get to subtract 1/2 of the sugar alcohols from our total carbs to get determine our net carbs.
This is a headache because there is a long list of hidden sugar alcohols to keep track of: xylitol, sorbitol, maltitol, mannitol, isomalt, lactitol, glycerin and the lone exception erythritol (which we get to subtract all of the carbs from)
Now, using our advanced net carb equation from above, the net carbs play out like this:
Total Carbs (23g) – Fiber (12g) – 1/2 of the Sugar Alcohol Glycerin (8g) = 7g of net carbs
Finally, we’ve got our answer.
There are plenty more subtle things to consider (like our own personal variability and responses to foods) but this should give you a strong handel on your quest to calculate net carbs in food for your keto diet.
If you’re up for it, let’s tackle one more net carb example.
TAKE ACTION> Download a list of SUGAR ALCOHOLS
Figuring out net carbs (sugar alcohol erythritol)
So now we’re onto sugar alcohols. We know that we will be subtracting 1/2 of our sugar alcohols from our total carbs when sorting out our net carbs.
In this example we look at the ever popular Quest Bar which has another popular (and yummy) sugar alcohol erythritol on the label.
For fun I’ll pick the Birthday Cake flavor
Let’s look for those pesky sugar alcohols again:
- xylitol
- erythritol (exception – Zero Net Carbs)
- sorbitol
- maltitol
- mannitol
- isomalt
- lactitol
- glycerin
This is what we find on the label.
We see erythritol which we know is a sugar alcohol.
Typically we subtract 1/2 of the carbs of sugar alcohols to determine out net carbs.
In this case we recognize that because Erythritol has zero net carbs we get to subtract all of the carbs from it.
Now, lets see the advanced method for determining net carbs:
Total Carbs – Fiber (or 1/2 the carbs from IMO) – 1/2 the carbs from Sugar Alcohols (other than erythritol)
= Net Carbs
Now we learn that our Quest bar plays out like this:
Total Carbs (24g) – Fiber (14g) – ALL of the Sugar Alcohol Erythritol (6g) = 4g of Net Carbs
The 4g of net carbs advertised on the package turns out to be legit! Well done Quest… well done!
TAKE ACTION> Download a list of SUGAR ALCOHOLS
Mr Skinny Pants Closing Thoughts
First, Mr Skinny Pants prides himself on making things easy and practical. (like the beginner example at the top of this article)
As you can see, he also REALLY wants you to succeed!
Sometimes, that means digging in and learning (like the advanced examples)
With that in mind, he would like to share something with you!
Let me first ask this question….
Are you new to keto?
If you are…
Mr Skinny Pants wants to share something with you!
Grab the Mr Skinny Pants 5 Steps to a Successful Keto Diet
Common questions about net carbs and keto:
- How to read food labels?
If you missed our examples… head back to the top of this article 🙂
- How many carbs should you eat per day on keto?
About 5 percent from carbohydrates which for most people will total of 20 to 30 grams of carbohydrates per day, depending on your height and weight.
- How your body handles fiber carbs?
Fiber can’t be broken down into sugar so it does not count toward your total carbs. Fiber is healthy in other ways.
- How your body handels sugar alcohol carbs?
Sugar alcohols typically have 1/2 the impact of regular carbs.
- Can you drink alcohol on a keto diet?
It’s not the best choice but… we’re human right? So Mr Skinny Pants says yes. Take a peek at our low carb food list which includes low carb alcohol.
- How much weight can I lose on keto?
We’ve had people lose 60+ lbs. One person even lost 200 lbs! Read her story If weight lose is your goal, you might enjoy things not to do, if you’re trying to lose weight.
- How long do I need to stay on the keto diet to lose weight?
It really varies. We find people start losing weight in as little as 3 days but we find it takes 2-5
- How much protein can I eat on keto?
Typically 15-20% of your total calories can come from protein on the keto diet.
by Mr Skinny Pants
So if imo are not considered to be actual deduction from carbs – how can companies get away with labeling a product as net carbs is 2 when they are subtracting 18 imo to get that number. Example- total carb is 24. Fiber is 4. Imo is 18 to make net carb 2. But if fda doesn’t recognize imo as fiber how can companies label their products this way bc it’s false and completely not accurate. ?
I THOUGHt calories weren’t counted on Keto so how can 15-20% of our total calories be from protein – how do I work that out.