Should Keto dieters use “total” or “net” carbs?

What are “carbohydrates”?

 Carbohydrates are one of the three major macronutrients, other than water which has no caloric content. Those three macronutrients are carbohydrate, protein, and fat. Every food is made up of one or a mixture of all these macronutrients.

Each of these nutrients is broken down once consumed in a process called metabolism. Through the process of metabolism these nutrients are converted to energy that can be used by the various cells in the body to fuel that cell’s function.

Proponents of low-carb diets such as Atkins, Paleo and the more generic Ketogenic (Keto) diet propose that a cause of obesity and many diseases, including diabetes and heart disease is consuming foods that in total provide an excessive amount carbohydrate.

These various diet plans are based on the consumption of food containing fewer carbohydrates, and more protein and fat.

 What are “net” carbs?

 The basis for the position that a diet should contain few carbohydrates is the undisputable fact that these foods, unlike foods high in protein and fat, cause significant spikes in serum glucose (blood sugar) which are indisputably correlated with obesity and a higher incidence of diabetes and metabolic syndrome. The most common carbohydrates that are used for energy metabolism are glucose, fructose, sucrose (which is one part glucose and one part fructose), and lactose (the carbohydrate found in dairy products), all of which can cause a significant increase in blood glucose.

There are some carbohydrates, however, that are digested in a way such that they do not cause an increase in serum glucose, nor any significant secretion of insulin. Fiber, which is contained in many plant foods is the most common of these non-digested carbohydrates that have little or no impact on blood glucose. The percentage of digestible carbohydrates to the non-digestible fiber varies from food to food. In an avocado, for example, 75% of the carbohydrate content is, in fact, fiber.

The Atkins Diet website defines “net carbs” as the total carbohydrates less fiber and sugar alcohols. Sugar alcohols (something quite different than common sugar) are another type of carbohydrate that is at least partially non-digestible, depending on particular type. The two that have the least impact on blood glucose are erythritol and xylitol. Erythritol is the clear winner have virtually no affect on blood glucose. You can learn more about erythritol and the other blood sugars in this 6-minute article.

The Atkins definition of definition of “net carbs” isn’t accepted carte-blanche by the low-carb community, since some of the sugar alcohols, most notably sorbitol and maltitol, can cause an insulin response when digested in more than trace amounts. And it creates a problem when seeking guidance on which foods are acceptably low-carb since online sources for food nutrients, such as the USDA nutrition database, have not historically broken out the sugar-alcohols and they are not broken out as line items on the government required Nutrition Facts label for packaged foods.

Since these sugar alcohols only appear in trace amounts in whole fruits and vegetables the argument over this point is moot for all whole foods, which is the only type of food you should be consuming if your health is a top priority.

Sugar alcohols are now beginning to appear in packaged candies and confectionary treats and some sugar-substitutes are now beginning to be made with these sugar alcohols. The low-carb world is left wondering whether and how to account for these foods containing sugar alcohols.

Should I use “total carbs” or “net carbs” to determine which foods I should be eating on a low-carb or keto diet?

Some proponents of low-carb diets recommend using total carbs (without deduction for the fiber and sugar alcohols) to determine your dietary intake. That’s not a good approach as it would discourage consumption of some the healthiest low-glycemic foods on the face of the earth, like an avocado whose total carb count is a relatively high 11.75 for one whole avocado, but whose net-carb count is only 2.86g and which I can confirm from personal experience and from the experience of my sister who is a Type 1 diabetic, that regularly consumes avocados, has somewhere between minimal and zero impact on serum glucose.

There is no rational argument for limiting fiber in a low-carb diet. In fact, most proponents of a low-carb diet would tell you that high-fiber foods like avocados are an essential element of a healthy low-carb diet. So healthy, in fact, that it holds the #2 spot on our list of the 10 most important foods in the world. And the #3 food on that list, flaxseed, is also high in total carbohydrates, yet has nominal blood sugar impact due to having a fiber content that is 90% of the total carbs.

The rationale behind that approach is that you might be confused by the sugar-alcohol content on packaged products bearing Nutrition Labels.  Why would this be an issue since the #1 rule of any legitimate diet, whether low-carb or not, is that you should cut all sugar and processed foods from your diet? If it has a Nutritional Label it’s probably a processed food you shouldn’t be including in your diet.  It’s that simple.

The only exception to this rule should be legitimate low-carb breads and sugar-substitutes. To avoid confusion, we feature these type products in specialized articles where we reveal the sugar-alcohol content of these products and tell you exactly how they affect blood glucose, if at all.

For everything else use our Carbs Calculator to compute the Net Carbs of more than 350 whole foods, including about any meat or vegetable you can find at the grocery store or farmer’s market.

So, wrapping it up … using “net carbs” is the best and most accurate way to determine which foods are truly appropriate on a low-carb or ketogenic diet. And using our Carb Calculator makes it easy to determine how to determine the net carb content of a food. In fact, it’s the ONLY carbohydrate amount we currently show in the calculator … because it’s number that matters