How to Calculate Net Carbs

Whether to count net or total carbs is a controversial topic within the low-carb community.

For starters, the term “net carbs” isn’t officially recognized or agreed upon by nutrition experts. In addition, due to conflicting and outdated information, figuring out how to calculate net carbs can be confusing.

In fact, the net carb claims on packaged foods may not reflect the number of carbs your body actually absorbs.

Luckily, knowing how your body processes different types of carbs may help you achieve your target blood sugar, weight loss and health goals.

This article looks at the science behind net carbs, provides simple calculations for determining your intake and discusses the pros and cons of counting net carbs.

What Are Net (Digestible) Carbs?

Net carbs are sometimes referred to as digestible or impact carbs. The terms refer to carbs that are absorbed by the body, including both simple and complex carbs.

Simple carbs contain one or two sugar units linked together and are found in foods like fruits, vegetables, milk, sugar, honey and syrup.

Complex carbs contain many sugar units linked together and are found in grains and starchy vegetables like potatoes.

When you eat a carb-containing food, most of the carbs are broken down into individual sugar units by enzymes produced in your small intestine. Your body can only absorb individual sugar units.

However, some carbs can’t be broken down into individual sugars, whereas others are only partially broken down and absorbed. These include fiber and sugar alcohols.

Because of this, most fiber and sugar alcohols can be subtracted from total carbs when calculating net carbs.

SUMMARY:Net (digestible) carbs are broken down into individual sugar units and absorbed into your bloodstream. However, your body processes fiber and sugar alcohol carbs differently than digestible carbs.

How Your Body Handles Fiber Carbs

Fiber is a unique form of carbs in terms of its digestion and effects on your body.

Unlike starch and sugar, naturally occurring fiber isn’t absorbed in your small intestine.

This is because the links between sugar units can’t be broken down by the enzymes in your digestive tract. Therefore, fiber passes directly into the colon (1Trusted Source).

However, its fate after that depends on what type of fiber it is.

There are two broad categories of fiber: insoluble and soluble. About two-thirds of the fiber you eat is insoluble, while the other third is soluble.

Insoluble fiber does not dissolve in water. It creates a bulkier stool and can help prevent constipation. This type of fiber leaves the colon unchanged, provides no calories and has no effect on blood sugar or insulin levels (2Trusted Source).

By contrast, soluble fiber dissolves in water and forms a gel that slows down food’s movement through your system and can help make you feel full (3Trusted Source).

After arriving in your colon, soluble fibers are fermented into short-chain fatty acids (SCFAs) by bacteria. These SCFAs help keep your gut healthy and may also provide a number of other health benefits.

Studies have shown that the fermentation of 1 gram of soluble fiber to SCFAs provides about 1–2 calories, depending on the type of fiber (4Trusted Source5).

Since about one-third of the fiber in most foods is soluble, a serving of food containing 6 grams of fiber would contribute up to 4 calories in the form of SCFAs.

However, while soluble fiber does provide a few calories, it doesn’t seem to increase blood glucose. In fact, the most recent research suggests that its effects in the gut help reduce blood sugar levels (6Trusted Source7Trusted Source).

Many studies have shown that soluble fiber may lead to better blood sugar control, increased insulin sensitivity and the absorption of fewer calories (8Trusted Source9Trusted Source10Trusted Source11Trusted Source).

On the other hand, one processed fiber called isomaltooligosaccharide (IMO) seems to be partially absorbed in the small intestine like non-fiber carbs, which may raise blood sugar (12Trusted Source13Trusted Source).

Recently, several food manufacturers replaced IMO with other forms of fiber in their products. However, IMO can still be found in a number of “low-carb” foods.

SUMMARY:Naturally occurring fiber is not absorbed in the small intestine. Gut bacteria ferment soluble fiber into SCFAs, which contribute minimal calories and have neutral or beneficial effects on blood sugar.

How Your Body Handles Sugar Alcohol Carbs

Sugar alcohols are processed similarly to fiber, with a few important differences.

Many sugar alcohols are only partially absorbed in the small intestine, and there is a lot of variation among different types.

Researchers report the small intestine absorbs 2–90% of sugar alcohols. However, some are only briefly absorbed into the bloodstream and then excreted in urine (14Trusted Source).

In addition, these sugar alcohols can have varying effects on blood sugar and insulin levels, although all are considerably lower than sugar.

Here is a list of the glycemic and insulin indexes for the most common sugar alcohols. By comparison, glucose’s glycemic and insulin index are both 100 (14Trusted Source).

  • Erythritol: Glycemic index 0, insulin index 2
  • Isomalt: Glycemic index 9, insulin index 6
  • Maltitol: Glycemic index 35, insulin index 27
  • Sorbitol: Glycemic index 9, insulin index 11
  • Xylitol: Glycemic index 13, insulin index 11

Maltitol is the most commonly used sugar alcohol in processed foods, including low-carb protein bars and sugar-free candy.

It’s partially absorbed in the small intestine, and the remainder is fermented by bacteria in the colon. It’s also been found to contribute about 3–3.5 calories per gram, compared with 4 calories per gram for sugar (15Trusted Source16Trusted Source17Trusted Source).

Anecdotally, maltitol has been reported to increase blood sugar levels in people with diabetes and prediabetes.

In terms of net carbs, erythritol seems to be the best choice all around.

About 90% of it is absorbed in the small intestine and then excreted in the urine. The remaining 10% is fermented to SCFAs in the colon, making it essentially carb-free, calorie-free and unlikely to cause digestive troubles (14Trusted Source18Trusted Source19Trusted Source).

Studies have shown that other sugar alcohols are also partially absorbed and may raise blood sugar, although to a lesser extent than maltitol. However, they seem to cause significant bloating, gas and loose stools in many people (14Trusted Source20Trusted Source21Trusted Source22Trusted Source23Trusted Source24Trusted Source).

Importantly, the controlled studies on sugar alcohols involved fewer than 10 people, and blood sugar levels weren’t always tested.

Overall, sugar alcohols don’t seem to have a major effect on blood sugar and insulin levels, but individual responses may vary, especially among those with diabetes or prediabetes.

SUMMARY:The absorption and fermentation of sugar alcohols vary widely. With the exception of erythritol, most are capable of raising blood sugar and insulin at least slightly.

Calculating Net Carbs in Whole Foods

Whole foods contain naturally occurring fiber. Therefore, you can simply subtract the fiber from the total carbs to get the net carbs.

The USDA Food Composition DatabasesTrusted Source provides complete nutrition information on thousands of foods, including carbs and fiber.

For example, a medium avocado contains 17.1 grams of total carbs, 13.5 grams of which is fiber (25).

So 17.1 grams of total carbs – 13.5 grams of fiber = 3.6 grams of net carbs.

SUMMARY:Whole foods contain fiber, which can be subtracted when calculating net carbs. Formula: total carbs – fiber = net carbs.

Calculating Net Carbs in Processed Foods

To calculate the net carbs in a packaged product, the more information you have, the better.

Calculating Net Carbs From Fiber

Most fiber can be completely subtracted from the total carbs listed on the nutrition label.

If you live outside the US, the “total carbohydrate” line already has the fiber removed and listed separately.

However, if the fiber isomaltooligosaccharide (IMO) is in the ingredients list, subtract only half of the fiber carbs.

Calculating Net Carbs From Sugar Alcohols

Generally speaking, half of the carbs from sugar alcohols can be subtracted from the total carbs listed on the nutrition label.

Erythritol is an exception. If it’s the only sugar alcohol in the ingredients list, its carbs can be completely subtracted from the total carbs.

This value may be different than the number of net carbs stated on the product label, since many companies subtract all fiber and sugar alcohol carbs when calculating net carbs.

For example, a maltitol-sweetened Atkins bar label states that it contains 3 grams of net carbs.

However, when subtracting only half the carbs from sugar alcohols, the net carb value is 8.5 grams: 23 grams of total carbs – 9 grams of fiber – 11 grams sugar alcohols (11 grams X 0.5 = 5.5 grams) = 8.5 grams of net carbs.

SUMMARY:A portion of fiber and sugar alcohols can be subtracted from total carbs to calculate net carbs. Formula: total carbs minus fiber (or half of IMO) minus half the carbs from sugar alcohols (other than erythritol) = net carbs.

Pros and Cons of Counting Net Carbs

There are pros and cons to counting net carbs, rather than total carbs.


  • Less restrictive: Counting net carbs may increase food choices. For instance, although blackberries, avocados and seeds are mainly fiber, they may be minimized on a ketogenic diet restricted to 20 grams of total carbs daily.
  • May promote higher fiber intake: Fiber-rich foods have been shown to promote fullness, decrease blood sugar and reduce calorie absorption. Limiting them may backfire in some cases (8Trusted Source9Trusted Source10Trusted Source11Trusted Source).
  • Reduced risk of hypoglycemia in people who use insulin: Taking insulin to cover all carbs without adjusting for high-fiber and erythritol-containing foods may potentially result in hypoglycemia, or low blood sugar.


  • Not 100% accurate: At this time, it’s not possible to calculate net carbs with complete precision due to the varying effects of processing on fiber, the combination of sugar alcohols used in products and individual response.
  • May not work as well for some with type 1 diabetes: While subtracting fiber carbs may help prevent low blood sugar in some people with type 1 diabetes, others report counting all carbs makes it easier to manage blood sugar.
  • May lead to high intake of sugar-free treats: Overindulging in bars marketed as “low in net carbs” may stall weight loss, increase blood sugar and trigger other health problems.

Ultimately, the decision about whether to count total or net carbs should be based on what works best for you.

SUMMARY:Counting net or digestible carbs may be helpful for some people, while others may prefer to count total carbs. The choice is a personal one.

The Bottom Line

The debate about whether it’s more accurate to count total or net carbs isn’t likely to go away anytime soon.

However, understanding how your body processes different kinds of carbs can help you manage your blood sugar, weight and overall health.

Calculating net carbs is one way to do this. The term “net carbs” simply refers to carbs that are absorbed by the body.

To calculate the net carbs in whole foods, subtract the fiber from the total number of carbs. To calculate the net carbs in processed foods, subtract the fiber and a portion of the sugar alcohols.

Nevertheless, remember that the “net carbs” listed on food labels can be misleading, and individual responses may also vary.

If you find that counting net carbs leads to higher-than-expected blood sugar levels or other issues, you may prefer to count total carbs instead.

The key is to eat the number of carbs that allows you to achieve your health goals, no matter how you count them.

What to Know About Using Alcohol to Kill Germs

A person cleans their phone, which is lying on a yellow tabletop, with an alcohol wipe. Share on Pinterest
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If you’re wondering whether alcohol — like ethanol or isopropanol — has the ability to kill germs on your skin and on surfaces in your home, the short answer is yes, it potentially can.

Alcohol has antimicrobial properties. This means that, at the right concentration (strength), it can destroy germs such as bacteria and viruses. But, as with most things, its effectiveness depends on various factors.

Let’s get into how well alcohol works at killing various germs, including the coronavirus that causes COVID-19 (SARS-CoV-2).

Can alcohol kill germs?

Alcohol kills germs through a simple chemical process known as denaturation.

Denaturation occurs when alcohol molecules break down the proteins present in the structure of germs. When the proteins break down and lose their structure, the cells can’t function properly. They lose their membrane protection, dehydrate, and quickly die.

This process is similar to what happens when you wash your hands with soap and water. However, soap is even more effective than alcohol.

The most widely used alcohol-based sanitizers contain either ethanol (ethyl alcohol) or isopropanol (isopropyl alcohol). Ethanol is chemically the same as drinking alcohol. You might have heard isopropanol referred to as rubbing alcohol.

Both are fairly effective at eliminating bacteria and viruses on your skin and on different types of surfaces. In general, ethanol is more powerfulTrusted Source than isopropanol, although it depends on the type of microbe you want to kill.

The Centers for Disease Control and Prevention (CDC)Trusted Source recommends an alcohol concentration of between 60 and 90 percent for disinfection purposes.

When looking for products like household cleaners or hand sanitizers that can kill germs, opt for ones that indicate at least 60 percent ethanol or 70 percent isopropanol as an ingredient.

Keep in mind that these products aren’t meant to be consumed. They won’t help kill germs that are already inside your body. Plus, ingesting these products poses life threatening health risks.

Can alcohol kill all types of germs or only some types?

At the required concentrations — between 60 and 90 percent — alcohol can kill a broad range of germs, including bacteria, viruses, and fungi.

For example, alcohol can eliminate common bacteria, such as E. colisalmonella, and Staphylococcus aureusOther bacteria, such as Enterococcus faecalis, are becoming more resistant to the effects of alcohol-based disinfectants.

Alcohol has also been shown to kill viruses such as herpes, hepatitis B, HIV, influenza, rhinoviruses, and coronaviruses, among others.

2020 study indicates that alcohol effectively destroys SARS-CoV-2, the virus that causes COVID-19.

However, alcohol isn’t effective against destroying the viruses that cause hepatitis A or polio.

Finally, alcohol is also effective at destroying fungi, such as Blastomyces dermatitidis and Coccinidiodes immitis, which can cause fungal diseases.

How to use alcohol effectively for disinfection

When choosing an alcohol-based disinfectant, remember to look for a product with an alcohol content of at least 60 percent.

Keep alcohol-based products out of reach of children and pets. Also remember that alcohol-based products are flammable and should be kept away from flames. Keep these products sealed to prevent evaporation, which can weaken the concentration of the alcohol.

Follow the guidelines below when using an alcohol-based product to disinfect your hands or household surfaces.

For your hands

Before using a new hand sanitizer, check to make sure the product doesn’t appear on the list of hand sanitizers to avoidTrusted Source provided by the Food and Drug Administration (FDA).

Follow these steps to use an alcohol-based rub to sanitize your hands:

  1. Remove any dirt or debris from your hands. Alcohol-based sanitizers are less effective when hands are visibly dirty.
  2. Apply the sanitizer to one palm. A dime-sized amount of liquid should be enough (or if you’re using wipes, one wipe). If the product label indicates how much to use, follow that.
  3. Rub your hands together, making sure to cover all the skin on both hands, including the backs of your hands, your palms, your fingertips, and in between your fingers.
  4. Keep rubbing until the sanitizer has been absorbed and your hands feel dry.
  5. Reapply sanitizer whenever you would normally wash your hands but don’t have access to soap and water.

For household surfaces

Follow these guidelines to use an alcohol-based product to disinfect your home:

  1. Wear gloves to protect your hands, and ensure that you’re working in a well-ventilated area.
  2. Use soap and water to remove any visible dirt or debris before disinfecting.
  3. Read and follow all instructions on the product label.
  4. Wipe down the surface. Ensure it remains visibly wet for at least 30 seconds. Some products may offer additional directions.
  5. Remember that viruses such as the new coronavirus can live on surfaces for up to a week, depending on the surface. Clean frequently touched surfaces at least once per day — more often if someone in your home is sick.

What else can kill germs on your hands or surfaces?

Using soap and water is the best way to kill germs on your hands. To wash your hands, wet them thoroughly with water, lather them with soap, and scrub for at least 20 seconds. Then rinse and dry them.

If you don’t have alcohol on hand to disinfect surfaces in your home, you can use a wide range of other products, including bleach.

The Environmental Protection Agency (EPA) has a list of disinfectants known to be effective against SARS-CoV-2. When using a new product, check to make sure it’s on the list.

Can drinking alcohol kill viruses and bacteria?

Drinking alcoholic beverages such as beer, wine, whiskey, or vodka won’t help your body fight off an infection.

When you drink, the concentration of alcohol that actually enters your bloodstream isn’t enough to effectively kill germs. This is true even at blood alcohol levels associated with potentially fatal alcohol poisoning.

Drinking alcohol-based hand sanitizers or cleaning products also poses serious risks, including:

  • seizures
  • coma
  • death

If you’re wondering whether, in a pinch, you can use an alcoholic beverage to disinfect your hands or household surfaces, you should know that it’s not an effective option.

Alcoholic drinks generally contain between 5 and 30 percent alcohol, so they aren’t effective as disinfectants. In addition, they aren’t formulated to remain on your skin or surfaces long enough to kill germs. This means they’ll likely evaporate too quickly to be effective.

The bottom line

At concentrations greater than 60 percent, alcohol effectively kills germs on your hands and household surfaces.

Microbes including bacteria, viruses, and fungi are susceptible to alcohol’s germicidal effects. This includes the new coronavirus that causes the respiratory disease COVID-19.

But alcohol-based sanitizers and disinfectants are not meant to be consumed. They won’t destroy pathogens inside your body.

It’s important to always follow the instructions on the product label for best results.


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