When it comes to following the keto diet, it’s vital to learn about the different types of carbohydrates that exist and how they impact your body.
Knowing your carb intake can make the difference between staying in ketosis or not.
Before you start thinking that all carbs are the same, you should know that certain carbs don’t have the same impact on your blood sugar compared to others — and they may affect which carbs “count” towards your daily intake.
This article discusses net carbs, how they differ from total carbs, how to calculate your net carbs, and their role in promoting weight loss.
What are Net Carbs?
Officially, the FDA doesn’t have a standard definition of what a net carb is, so some peoples’ take on net carbs may differ. But in a nutshell, net carbs are what you’re left with after subtracting grams of fiber (and sugar alcohols) from the total carbohydrates per serving.
The concept behind net carbs boils down to our body’s digestive processes. Because certain carbohydrates like fiber and sugar alcohols aren’t fully digested by the body or cause significant changes to blood sugar, many people state that they don’t count towards your total carbohydrate intake.
We’ll get into the details of how to calculate net carbs later on in this article.
Why Do Net Carbs Matter?
Net carbs are important because they are a reflection of the glycemic index of foods. The glycemic index (GI) of foods determines how quickly their carbohydrates are digested and enter the bloodstream. It is measured on a scale from 1-100, with 50 g of glucose being the reference for a high-GI food[*].
Foods that have a high glycemic index are also known as impact carbs. In other words, these foods increase your blood sugar levels. When high-GI carbs enter your bloodstream — unless they’re immediately used for physical exercise — they typically contain more energy than your body can successfully use in one go. This extra energy gets stored as glycogen in your muscles and liver or as body fat.
Impact carbs can be very damaging to your health (and waistline) when you consume them regularly in high amounts. Foods that are high in impact carbs also tend to be lower in fiber.
Studies find that diets with large amounts of high-GI/impact carbs affect metabolism, increase complications of chronic diseases like polycystic ovary syndrome (PCOS), and may even increase the risk of certain cancers[*][*][*].
On the other hand, foods that are low-GI tend to be higher in fiber and nutrient-dense compared to some high-GI foods.
Guiding your food choices by net carbs can help you focus on getting your carbs from foods that not only have fiber but are likely to have other essential vitamins and minerals.
Net Carbs vs. Total Carbs
While net carbs are about subtracting carbohydrates that aren’t fully digested by the body, total carbs do not take this into consideration.
The Nutrition Facts Label will list the total grams of carbohydrates per serving in a food, which is the sum of all carbohydrates. This sum includes natural sugars and starches, added sugars, dietary fiber, and sugar alcohol.
When looking at the total carb content of a food, especially processed food, it can help you make better choices about the food that you eat.
You can see if food manufacturers are adding large quantities of sugar alcohols to lower the net carbs of food, or if your food has a significant amount of filling fiber.
Using net carbohydrates gives people following a keto diet more options for getting nutrient-dense foods into their diet. However, there is also the risk of potentially miscalculating your net carbs and getting kicked out of ketosis.
Choosing to count total carbs instead of net carbs can be the easiest way to guarantee that you’re within your carb range for ketosis, but eating this way can be more restrictive (by limiting your food options, for example).
Start calculating your net carbs or total carbs and other macros using our free keto calculator.
Net Carbs, Fiber, and Sugar Alcohols
The carbohydrates subtracted in the net carb formula include both fiber and sugar alcohols. Foods that are low in net carbs are usually low-GI and tend to either be high in fiber, high in sugar alcohols — or have a combination of both.
Low-GI or low-impact carbohydrates are digested at a much slower rate. Due to this prolonged release of glucose into your bloodstream, insulin spikes are less likely to happen, resulting in sustained energy levels.
Fiber is a type of carbohydrate that can’t be broken down into digestible sugar molecules and is instead fermented by the bacteria in your colon. It is crucial for optimal digestive functions and overall health[*].
There are two main types of fiber: soluble and insoluble fiber.
Soluble fiber is the type of fiber that can be diluted in water, creating a gel-like substance. Soluble fiber can make you feel fuller for a longer period, helping to promote weight loss.
This happens because this substance slows down the process of absorption of food in the body. Even though it contains a small number of calories, it doesn’t seem to affect your blood glucose levels. Soluble fiber also feeds your gut bacteria, ensuring a healthy microbiota[*].
Insoluble fiber, on the other hand, is the fiber that does not dissolve in water, has no calories, and its function is to help you have healthy and regular bowel movements.
When buying processed goods, reading food labels is extremely important as some manufacturers may place a type of processed fiber in their foods called IMO, often listed as tapioca fiber in ingredient lists.
IMOs or Isomaltooligosaccharides can occur naturally in foods like honey or fermented foods like miso and soy sauce. When manufactured on a commercial scale, IMOs are processed from cereal crops like wheat, barley, oats, tapioca, rice, potato, pulses (peas, beans, lentils), and others.
Studies on IMOs show that they may raise blood sugar levels[*]. Currently, the FDA states that there is insufficient evidence as to whether they provide benefits to human health and the EU prohibits health claims for oligosaccharides[*][*].
Learn more about fiber in this podcast episode with Dr. Michael Ruscio.
Sugar alcohols, also known as polyols, are comprised of sugar molecules and alcohol molecules. They do not, however, contain ethanol, the compound that makes you intoxicated.
Sugar alcohols are naturally occurring in a vast number of fruits and vegetables but they’re mostly used as alternative sweeteners. The most well-known ones are sorbitol, erythritol, xylitol, and maltitol. They are commonly found in sugar-free foods[*].
Although they are considered alternatives to sugar, keep in mind that these polyols do contain calories and some of them might affect your blood sugar and insulin levels.
How to Calculate Net Carbs
When it comes to carb counting, one thing that can get a little confusing is the “net” carbohydrate situation. Don’t worry, because it’s not nearly as difficult as it sounds.
Recall that the formula for net carbs is: total carbs – (fiber + sugar alcohols).
If you’re a beginner at calculating net carbs, it is easiest to start by calculating them in whole foods. Whole foods are very simple in that they consist of natural sugars and fiber, without having to deal with sugar alcohols.
Take an avocado, for example. It’s one of the most important whole foods in a keto diet not only for its dense nutrient content but also for the immense quantity of healthy fats it contains (such as omega-3s and omega-6s).
A medium avocado contains:
- 21 g fat
- 2.7 g protein
- 12 g carbs of which 9.2 g is fiber
- 12g carbs – 9.2g fiber = 2.8 grams of net carbs
Sugar alcohols can be a bit more difficult to calculate, as the calorie content of sugar alcohols differs. As a general rule, you can divide grams of sugar alcohols in half and subtract them from your total carbs, but you can read our guide on sugar alcohols here for more info.
Reading the food label is going to be the easiest way to figure out what carbs are in your diet, but apps and online tools can also be helpful.
The USDA has a tool that contains all the nutrition information about thousands of whole foods and more, to help you on your keto journey.
The Role of Net Carbs in Weight Loss
In addition to monitoring calorie intake, choosing foods that are low in net carbs is important in supporting weight loss.
Foods that are low in net carbs tend to stabilize blood sugars, reduce food cravings, and increase satiety to reduce overeating. Choosing whole foods that are naturally low in net carbs can also help you get the nutrients you need to support your metabolic health.
The keto diet is based on this system and is one of the reasons why the keto diet can help people lose weight [*].
Tracking net carbs is a great way to make smart choices about the carbs you eat and maximize your intake of fiber to support a healthy metabolism and body. You can use this information to integrate low net-carb foods into your daily diet and form a plan that will keep you in ketosis.
Completely removing any nutrient from your diet is never the best way to ensure overall vitality. However, maintaining a balance, especially if you’re very physically active, is the key to getting your nutritional needs met.
The main goal of a low-carb or keto diet is to replace most carbohydrates with healthy fats and protein. But it’s also important to know how to most effectively use your carbohydrates.
You can use high-glycemic carbs, for instance, to help support your workouts or for sports performance. If you think your workouts warrant a few extra carbs, you might want to check out a cyclical ketogenic diet or a targeted keto diet.
Frequently Asked Questions on Net Carbs
What is a net carb vs. regular carb?
Regular carbs, or total carbs, include the total amount of natural sugars and starches, fiber, and sugar alcohol in a product. Net carbs are the result of subtracting fiber and sugar alcohols from the total carbs due to the body not fully digesting these carbs.
When doing keto, should I track net carbs or total carbs?
If you’re new to keto, it may be easier to calculate total carbs to prevent getting out of ketosis. However, if you want to focus on low-GI foods and fiber intake, tracking net carbs may be more suited to your carb counting needs.
Can counting net carbs help me lose weight?
If combined with calorie restriction, counting net carbs can potentially help you lose weight. Foods with low net carbs may be high in fiber, which may reduce food cravings and increase satiety between meals. Together, these things can help prevent you from overeating.