Skip to content

How to Calculate Net Carbs for Weight Loss

Calculating net carbs may have risen to popularity due to low-carb diets, but the technique can teach us all a lesson about food quality.

Additional reporting by Kelsey Hampton, MS, RDN, LD, CSSD

In more recent years, you may have started to notice the term "net carbs" in bold, bright graphics on the front of food packages.

Counting net carbs is a concept that has been around for a very long time. In fact, one of the first utilizations of calculating net carbs was for those who take insulin to manage their diabetes.

So, why recently are so many food manufacturers advertising net carbs, and why are your friends and family raving about their new favorite "0 grams net carb" protein bar? It can be attributed to the rise of the keto diet as well as the staying power of low-carb diets.

Despite their connection to many diets, net carbs are relevant to everyone. Calculating net carbs provides a number that can help you understand and decipher (for the most part) good quality food products at the store and may even help you lose some unwanted body fat.

(Related: 8 Grocery Items That May Soon Be in Short Supply.)

What are net carbs?

Calculating net carbs is a way to measure the carbohydrates your body actually digests. The "Total Carbohydrates" line on every Nutrition Facts label indicates the total amount of sugar, fiber, and other carbohydrates in a food. The thing is, your body doesn't treat all of these carbs the same way.

  • Carbohydrate is a macronutrient that contains four calories per gram. Carbs are made up of long chains of sugar molecules.
  • Dietary fiber is a form of carbohydrate; however, your body does not digest fiber, so it does not provide calories like other forms of carbohydrates.

When you take the total amount of carbs in food and subtract out the dietary fiber that does not contain calories, you get, drum roll please, net carbs, which is the remaining carbs that contain calories.


Essentially, the net carb theory is that certain carbs don't need to be tallied as carbs for the day.

For example, there are 40 grams of carb in a cup of cooked quinoa and 5 grams of fiber.

40 grams total carbs 5 grams fiber = 35 grams net carb. This cup of quinoa only has 35 grams of digestible, calorie-containing carbohydrate.

Why would you want to calculate net carbs?

Calculating net carbohydrates provides a more accurate number of calorie-containing nutrients in the foods we consume.

There are multiple reasons people may choose to calculate net carbs:

  • Diabetics use net carbs to dose their insulin.
  • You can use net carbs to lose weight by identifying low-calorie foods.
  • The keto diet requires a low-carb intake to drive the body into a state of ketosis.

How to use the power of net carbs to lose weight.

To lose weight, you have to create a calorie deficit by increasing calories burned and reducing calories ingested. When counting net carbs to lose weight, you can start by reducing the total calories you consume. Reducing total calories also naturally reduces your carb intake.

You can also use net carbs to identify which foods to eat more of. You can do this by choosing high-fiber foods; the more fiber in a carbohydrate food product, the lower the net carb will be.

Let's use white rice, quinoa, and black beans as an example. They all contain about 40 grams of carb per one cup (cooked) with varying amounts of fiber.

Because each of these foods has different fiber content and essentially the same total carb, it means they all have different amounts of net carb.

  • White rice: 44 g total carb – 0.5 g fiber = 43.5 g net carb
  • Quinoa: 40 g total carb – 5 g fiber = 35 g net carb
  • Black beans: 40 g total carb – 15 g fiber = 25 g net carb

As you can see, the black beans have the lowest amount of net carbs per serving. White rice has the most.

The individual trying to reduce carbs to lose weight should choose the lower-net-carb beans more often than the other starches. In doing so, you will consume fewer digestible carbohydrates that contribute calories and impacts blood sugar.

Nearly all carb restriction diets, including keto and Atkins, focus more on restricting net carb rather than reducing total carb.

Let's go over the difference between fiber and sugar alcohols.

Another ingredient you may have noticed on Nutrition Facts labels—especially manufactured foods like protein bars and sugar-free drinks, sugar-free candy, and sugar-free gum—is sugar alcohol.

Sugar alcohols are used in processed foods to add sweetness while providing fewer calories than table sugar. They can provide fewer calories than sugar because sugar alcohols are incompletely digested. Remember that fiber is not digested at all. These sweeteners are also quite different than dietary fiber, as many of them are not naturally occurring.

Types of sugar alcohols include:

  • Erythritol
  • Sorbitol
  • Maltitol
  • Mannitol
  • Xylitol

Similar to fiber, you can subtract sugar alcohols from the total carbohydrate grams to calculate net carbs. However, the body doesn't process all sugar alcohols the same. For most sugar alcohols, you can only subtract half of the total sugar alcohols in the net carb equation. Other sugar alcohols (like erythritol) are not digested, so you can subtract the full gram.


Fiber provides many benefits to the body outside of being a non-digestible carbohydrate. Fiber may help to lower cholesterol, improve digestive regularity, and helps increase satiety.

Sugar alcohols can serve as a form of prebiotic to feed good bacteria in your digestive tract, which is a plus, but they are also known to cause bloating, diarrhea, and gas, and long-term use is inconclusive in terms of health concerns.

RELATED: The science-backed way to curb your sweet tooth in 14 days.

Is calculating net carbs healthy or a useful method to lose weight? Would you recommend it?

Calculating net carbs can be useful for someone trying to lose weight because it encourages intake of high-quality food, namely fiber. As a general rule of thumb, foods in their natural state that are high in fiber are going to be amongst the best quality options compared to those with similar carb and less fiber.

Looking at fiber content in processed items can also help you determine a better quality option. Next time you are at the store trying to decipher which whole grain cracker is best, look for the one that provides the most fiber per serving.

Additionally, those who eat a high fiber diet tend to weigh less than those on a low fiber diet. The American Heart Association recommends consuming 25 grams of fiber for women and 38 grams of fiber per day for men, so whether counting net carbs or aiming to reach a minimum amount of fiber each day, both options will likely help you make improvements in your nutrition.


Calculating net carbs can be beneficial for weight loss, weight maintenance, and improving intake of overall food quality. We don't have a set amount of net carb an individual should have in a day; rather, this number is specific to your goals, activity level, and related health conditions.

For more healthy eating news, make sure to sign up for our newsletter!

Melissa Rifkin, MS, RDN, CDN
Melissa is a Connecticut-based registered dietitian with over 15 years of experience, including clinical and outpatient settings, and runs the popular nutrition education Instagram account, Confessionofadietitian. Read more about Melissa
Filed Under