For a keto diet to yield the most effective results, you need to be able to track the foods you’re eating.
Without proper tracking, you will not be certain you’re adhering to the diet, leaving you struggling to make progress.
Because the keto diet so heavily focuses on maintaining a low carb intake, your ability to track the number of carbs you eat, and then to calculate the net carbs from that number, is vital to your dieting success.
What are net carbs?
During ketosis, your food intake should be high in fats and moderate in proteins, while remaining low in carbs.
However, calculating net carbs is not the same as just counting up the number of grams of carbs you eat in a day.
The net carbs number is the total number of dietary carbohydrate grams you ingest in a day after subtracting the total fiber grams you ingest.
So if you eat 35 grams of carbs in the day and 20 grams of fiber, your net carbs are 15 grams.
As long as you’re tracking everything properly, the actual calculation of net carbs is straightforward math. But there are a few aspects of counting net carbs that can complicate things a bit.
Types of fibers
Before getting into the maths of calculating net carbs on keto, let’s discuss how fiber works in the diet.
Fiber appears in food as either insoluble or soluble.
As a general rule, most people receive about two-thirds of the fiber in their diets from insoluble fiber, while about one-third of the fiber most people eat is soluble fiber.
Insoluble fiber: An insoluble fiber is one that cannot dissolve in water.
It has no calories. It allows people to have more normal bowel movements regularly.
Soluble fiber: A soluble fiber will dissolve in water, almost creating a gel-like substance in the body.
Soluble fiber will make you feel more full for a longer period of time by preventing the body from absorbing food as quickly.
Some manufacturers may place a type of processed fiber in their foods, called IMO.
This type of fiber actually may raise blood sugar levels, acting a bit more like non-fiber carbohydrates.
So you may want to watch for the inclusion of IMO fiber in any processed foods you’re considering and avoid eating those foods.
Why is measuring net carbs important?
As the T.H. Chan Harvard School of Public Health explains, fiber is a type of carbohydrate.
However, unlike other types of carbs, which cause the body to produce insulin and glucose, fiber is not broken down into sugar molecules.
Insulin carries the glucose through the body in the bloodstream.
With enough glucose available, the body does not have to burn fat for energy, which inhibits weight loss.
But with extra fiber available in the diet, the body is better able to regulate its use of sugars like insulin and glucose.
Because fiber passes through the body without being digested, it is able to help a person better control hunger and blood sugar levels.
So when counting carbs, it’s not an accurate reflection of the food you’re eating if you treat carbs that produce insulin and glucose the same as fiber.
Essentially, the idea behind calculating net carbs is to give you the net effect of eating a particular type of food in terms of the number of grams of carbohydrates that you’re ingesting.
Net carbs should give you a truer picture of your diet versus just calculating carbs alone.
How sugar alcohols affect net carbs?
Despite its name, sugar alcohol has nothing to do with fruity alcoholic drinks.
Instead, a sugar alcohol consists of a natural organic compound.
People typically don’t digest sugar alcohols easily, which may lead to digestive problems if you eat these types of foods too often.
Sugar alcohols sometimes occur in natural foods, but they’re most often used as bulk sweeteners or alternative sweeteners in an effort to reduce the number of calories in food, according to a European Food Research and Technology study.
Some pre-made products that call themselves sugar-free often will contain sugar alcohols.
If a food contains sugar alcohols, it will list them on the nutritional label.
This means you have to calculate the net carbs for this type of food in a slightly different way.
When it’s time to calculate net carbs for foods with sugar alcohols, the Diabetes Teaching Center at the University of California, San Francisco, says you’ll want to treat 1 gram of sugar alcohol like 0.5 grams of fiber.
So if a food has 15 grams of carbs, 8 grams of fiber, and 8 grams of sugar alcohols, the net carbs would be 3 (as the sugar alcohol would count the same as 4 grams of fiber).
To throw in another layer of confusion, not all chemicals in sugar alcohols affect the body in the same way.
Chemicals like polydextrose will affect people differently than sugar alcohol like lactitol or xylitol. Different people react to different sugar alcohols too.
Studies are continuing to measure the way each of these chemicals affect the human body.
As a general rule in the keto diet, it’s recommended that you avoid ingesting foods that contain a large amount of sugar alcohols.
Avoiding sugar alcohols also helps to keep the net carbs calculations as simple as possible.
How to read net carbs on nutrition labels?
Some food labeling and nutrition labeling will give you the net carbs number, so you don’t have to calculate this yourself. (This type of label is more common in Europe.)
In other types of labels, you’ll have to do the subtraction yourself (common in North America).
Look at the nutrition label.
If the label lists the amount of fiber or dietary fiber as a subcategory of the carbohydrates or total carbs, you’ll have to subtract the number of grams of fiber from the number of grams of carbs to obtain the net carbs number, according to the Diabetes Teaching Center at UCSF.
On the other hand, if a nutritional label shows the number of grams of fiber separately from the number of grams of carbs, this means the carbs number is actually the net carbs number.
If you’re still a bit c0nfused, look more closely at the nutritional label, especially at the carbs line.
The word “carbs” or “carbohydrates” should be in bold type on the label, which shows that it’s a primary category.
Directly underneath the carbs line should be a sugars line in a non-bold type. (It also may be indented slightly.)
This indicates sugars are a subcategory of carbs. (It’s possible there will be other subcategories listed under carbs.)
If fiber or dietary fiber is listed near sugars in non-bold type underneath carbs, this means the nutrition label is listing fiber as a subcategory of carbs, and you’ll have to perform the net carbs calculation yourself.
However, if fiber is listed in bold type and it’s not directly under the carbs line, fiber is not a subcategory of carbs on this type of label, and the carbs line shows the number of net carbs.
If you have a type of food that doesn’t contain a nutrition label, such as with fresh fruit or vegetables, the USDA maintains an online database that contains all of the nutritional values. (This database also has numbers for processed foods.)
Pros of relying on net carbs
Understanding net carbs will help you have more accurate results in measuring progress on your keto diet, especially when it comes to losing weight.
Even though the body cannot digest fibers, it still attempts to digest them.
This means it cannot digest the other types of carbs as quickly, which is beneficial for keeping blood sugar levels at an optimal level.
With additional fiber in the diet, the body may take a few hours to digest the food rather than less than an hour.
This helps people avoid having insulin spikes.
With a food that’s high in fiber, the bloodstream absorbs the sugar steadily over time, allowing the body to maintain a more natural level of insulin.
The benefits of including plenty of fiber in your diet include things like reduced risk of cancer, reduced blood pressure, better weight control, and improved gastrointestinal function, according to The American Journal of Clinical Nutrition.
This means that taking the time to calculate net carbs can give you a much better picture of the types of food you’re eating and your overall health picture.
Another benefit of calculating net carbs is that you don’t have to worry about calculating intake of sugars separately.
The net carbs calculation gives you a picture of all types of carbohydrates eaten, including sugar. (Remember, sugar grams are different from the sugar alcohol grams we mentioned earlier.)
Cons of relying on net carbs
Using net carbs in your tracking for the keto diet means you have to spend more time doing calculations versus using carbs alone.
As we explained above, figuring out just how many net carbs you are ingesting can be a little confusing, especially for people who become frustrated trying to read nutritional labels.
And if you’re eating foods with sugar alcohols, it adds to the confusion of the calculation.
But most people appreciate the way that the net carbs calculation gives you a better picture of your overall health and your progress on the keto diet.
The other potential drawback of relying on net carbs comes when you just glance at a processed food label or box, where the food’s manufacturer has listed net carbs on the front of the product label in large print, trying to entice you to purchase the food.
Unfortunately, these marketing numbers for net carbs don’t have any consistency in how they’re calculated.
For example, a particular manufacturer may count 1 gram of sugar alcohol the same as 1 gram of fiber in the marketing number, which is different from the UCSF recommendation we mentioned earlier.
Relying on this marketing number in your calculations can give you an inaccurate number for your keto diet tracking.
It’s always best to do your own net carb calculations using the nutritional label for the product.
Additionally, some researchers believe net carbs don’t give a realistic picture of a person’s eating habits.
Johns Hopkins Medicine even says net carbs are a marketing ploy from food makers that leads to confusion, rather than being helpful.
Net carbs vs Total carbs
When you choose to use net carbs for your keto diet tracking calculations, you’ll receive a few benefits over using total carbs in the calculation.
High fiber diet: Using net carbs in the calculation gives you the incentive to eat a diet that’s higher in fiber.
Because net carbs subtract fiber grams from carbohydrate grams, you can eat more high fiber foods, so you won’t feel as deprived on the diet, while receiving the high fiber diet benefits we mentioned earlier.
More food options: When you use net carbs, you’ll be able to eat many types of foods.
For example, you might not want to eat any food that has 10 grams of total carbs per serving on your diet.
This limits the types of food you can eat. But if you rely on net carbs, many more foods will fit in the sub-10 grams per serving category.
Although having to perform various calculations as part of your keto diet can seem a little frustrating, taking the time to figure out the correct numbers about the foods you’re eating should help you have a higher level of success in your dieting.
Because net carbs provide a more realistic picture of the carbohydrates and fibers you’re eating, for most people, this is one calculation that’s well worth the time spent on it.
Also net carbs provide a clearer look at your eating habits, this calculation should help you have less frustration while trying to stick to your keto diet.