What The Heck Are Net Carbs?

I get a lot of questions from members who want to know what is meant by "net carbs." They want to know how to define net carbs and how to calculate them if they aren't listed on a food label.

As you may be aware, there is considerable concern and confusion in regard to the nutritional labeling of food products in the low carbohydrate food industry. Basically, the net carb count came about because, although fiber is technically a carbohydrate, it doesn't affect blood sugar levels and is very good for you. So, the health people figured that they could encourage people to eat more fiber if it didn't count against them in a low-carbohydrate diet.

Pretty clever of them! Then they invented all these artificial sweeteners that also do not affect blood sugar levels. This is where the net carbohydrate count comes in. It refers to the amount of carbohydrate actually "seen" by your body as being a carbohydrate.

One example of a carbohydrate that doesn't count is cellulose, an insoluble fiber that imparts zero calories per gram. Cellulose is not digested and passes through the body mostly unchanged. Still, the label includes cellulose in the carbohydrate count. That's why some of the numbers on labels -- for total carbohydrates and total calories -- don't always add up.

Regulations governing foods and supplements define "carbohydrate" as the remaining nutrient after protein, fat, moisture and ash have been subtracted from the total weight of a product. This sweeping definition, unbelievably held over from the mid-1800s, does not accurately reflect current scientific data. This definition is still in place nonetheless.

Carbohydrates such as glycerol are digested but are not converted by humans into glucose -- or at least not immediately. That means you're likely to burn them off before they stick. You don't need to tally these carbohydrates, but the government now requires supplement manufacturers to count them and put them on the label.

So, what does this mean to you? How do you calculate the "net carb" count?

First, to determine net carbohydrates in food, you will need to use the Nutrition Facts on the label. Take the total carbohydrates gram count and subtract the dietary fiber and any glycerin and/or sugar alcohols. (Sugar alcohols include things like Maltitol and Lactitol, but Lactitol is only half the carbohydrates of sugar. Artificial Sweeteners such as Splenda, NutraSweet, and others have very little to no carbohydrates.)

Since those three things do not significantly increase the blood sugar levels, they should not count against the carbohydrates that can impact your blood sugar, therefore you will continue to burn glycogen for energy.

Carbohydrates that affect your blood sugar are called "impact carbs." Once you subtract the non-impact carbs from the total carbohydrates, you will get the net carbs. For example, the total carbohydrate listing on a label might say the bar includes 20 grams of carbohydrates. But, after you finish reading the rest of the label, you might determine that the bar contains only 3 grams of carbohydrates for all practical purposes. That's three glucose grams and 17 non-glucose grams. That's a huge difference.

Labels often spell it out for you. Manufacturers are now providing additional statements, usually placed below the Nutrition Facts box. There you will find an explanation of which carbohydrates contribute to calories and which do not.

For example, the label on a nutrition bar might state "Total Carbs: 20 grams -- 15 grams are from glycerin (glycerol) and 2 grams are from Maltitol, both of which have a negligible impact on normal blood sugar levels." That means the bar provides only 3 grams of carbohydrates. That's a low-carb bar for all practical purposes, despite what else the label says.