Whether you’re following the Atkins® Diet, the Ketogenic Diet, Paleo or just trying to limit your carbs, “experts” will tell you it’s important to track and limit how many carbs you’re eating.
But…if you ask them how you should count your carbs? Well, that’s a whole different story.
There are two opinions here.
- Count the total carbs you consume
- Only count the net carbs you consume
The basic idea behind counting net carbs versus total carbs is that not all carbs are created equally, and therefore, will be used by your body differently.
While everybody is unique, many people find tracking net carbs to be a helpful way to reach their goals.
Before we jump in and learn what net carbs are and how to calculate them, let’s go over the basics.
How To Calculate Net Carbs
Simply put, carbohydrates are the sugar, fiber, and starches found in foods like fruits, vegetables, grains, and dairy that you eat. That’s why sugar is also listed under the carbohydrates section of a nutrition label—because sugar is a carb!
PSA: butter is not a carb so you can still enjoy it on a low-carb diet.
Carbs are your body’s go-to source for energy. Any time you eat carbs, your body will try to break those carbs down into simple sugars (glucose) for energy.
All carbs fall into two categories—simple and complex—based on how easy they are for your body to digest. Most food and beverage items (whether natural products or man-made) will have both simple and complex carbs in them. This is where the concept of net carbs comes into play.
What are net carbs?
Net carbs are defined as the carbohydrates that your body actually digests and absorbs. That’s why many people refer to net carbs as digestible carbs.
Carbs that are digested easily and quickly by your body are called simple carbs. Why? Because they’re simple for your body to break down quickly into glucose for energy. Simple carbs are found in things like table sugar and regular pasta.
Meanwhile, carbs that are harder for your body to break down and digest for energy are called complex carbohydrates. Complex carbs are commonly found in vegetables, whole grains, nuts and fruits which are usually high in fiber.
Fiber is one of the complex carbs that your body is not able to digest and therefore, its value can be subtracted from total carbs when you’re calculating net carbs. However, fiber isn’t the only complex carb you have to be on the lookout for. Let’s dive into all of the indigestible carbs you can subtract to count net carbs.
Fiber is different from other carbohydrates because it can’t be broken down by the enzymes in your small intestine where most carbs are digested.
There are two types of fiber: insoluble and soluble. Insoluble fiber passes into the large intestine where it is eliminated through the stool. Soluble fiber is fermented by the colon into short chain fatty acids. These short chain fatty acids are important because they play a key role in keeping the gut healthy 1.
When calculating net carbs, you can subtract the total amount of dietary fiber from the total carbs per serving.
Sugar alcohols are used to add sweetness to many low carb foods. Your body processes sugar alcohols fairly similarly to how it processes fiber, but not all sugar alcohols are created equal either.
Erythritol is a sugar alcohol that is naturally found in fruit and some fermented foods like pears, soy sauce and corn. Based on current research, erythritol has the lowest glycemic index (GI) of all sugar alcohols on the market. This means it should have little to no impact on your blood sugar level. Research also has suggested that erythritol isn’t fully digested by your body. One study found that 90% of erythritol leaves your body through your urine. Because of this, you can subtract the total value of erythritol when calculating net carbs.
However, other sugar alcohols like malitol, sorbitol, isomalt, and glycerin do affect your blood sugar and are partially digested by your body. Because of this, most experts recommend dividing their total number of grams per serving in half and then subtracting that number from the total carbohydrates.
To identify what sugar alcohols, if any, are present in the food or drink you're enjoying, simply check out the nutrition facts panel. Sugar alcohols will be listed under the Total Carbohydrate section. They may be listed organically simply as "sugar alcohols" or they may be called out specifically by name. If you can’t tell what sugar alcohol is used based on the nutrition panel, simply check out the ingredients list.
Allulose is a rare sugar that’s found in maple syrup, figs and raisins. While it has the same texture and sweetness as regular sugar, Allulose has only 10% of the calories and has a low glycemic index (GI).
Because of this, you can also subtract the entire value of Allulose from the total carbs per serving when calculating net carbs. However, depending on the label for the food you're reading, you may not even have to.
Earlier this year in April, the FDA declared that Allulose could be excluded from the total and added sugar section of a nutrition facts panel. In their decision, Susan Mayne, Ph.D., director of the FDA's Center for Food Safety and Applied nutrition shared, "The latest data suggests that allulose is different from other sugars in that it is not metabolized by the human body in the same way as table sugar. It has fewer calories, produces only negligible increases in blood glucose or insulin levels, and does not promote dental decay."
This is actually the first time in history that the FDA has ever allowed a sugar to not be included in the total or added sugars section of a nutrition label. On top of that, the FDA is permitting companies to use a revised, lower calorie count on their label if they use Allulose.
How do you calculate net carbs?
When you’re calculating net carbs, the first thing you need to do is look at the total carbs per serving on the food or beverage item you’re about to consume. Next, look to see if any dietary fiber, sugar alcohols, or allulose are listed under the Total Carbohydrate section on the nutrition facts panel, and if so you can subtract the total value of each. That simple formula should look a little like this:
However, if you see a sugar alcohol listed under the Total Carbohydrate section that isn’t erythritol, you can divide its value in half and subtract that number from the total carbs. An example of what that formula could look like is below.
If your head isn’t spinning already, let’s take look at two examples of how to calculate net carbs.
Looking at the nutrition facts below, you’ll notice a cup of strawberries has 11 grams of carbs, and 3 grams of fiber. 11 – 3 leaves us with 8 grams of net carbs. Easy, right?
Now, let’s take a look at a low carb snack that uses sugar alcohols. The nutrition facts panel for HighKey’s Chocolate Chip Mini Cookies has 11 grams of total carbs, 2 grams of fiber and 7 grams of erythritol per serving. 11 – 2 – 7 leaves us with 2 grams of net carbs.
To make things easier, many low carb and keto products will list the net carbs on the product label, but it is still a good idea to know how to calculate them yourself if necessary.
The Bottom Line
Net carbs can be a wonderful tool to utilize when following a low carb or keto lifestyle. By subtracting out the grams of fiber from the total grams of carbohydrates, you are only counting the carbs that are actually being digested and absorbed. This gives you more flexibility to incorporate nutrient rich, high fiber foods that leave you feeling full and support overall health.