What are net carbs and total carbs?
Net carbs are simply the total carbohydrates in a food minus its fiber and any sugar alcohols. Because the human body cannot digest fiber, it does not raise blood glucose levels and therefore does not need to be counted towards your total carb intake. This is why it’s perfectly acceptable to include lots of leafy greens and green vegetables, as well as some fruit, in a low-carb / ketogenic diet.
What are sugar alcohols?
Sugar alcohols are reduced-calorie sweeteners often found in foods labeled “sugar free” or “no sugar added.” They have less of an impact on blood glucose levels than other carbohydrates. Types of sugar alcohols include sorbitol, mannitol, xylitol, isomalt, erythritol, glycerol, and hydrogenated starch hydrolysates.
Sugar alcohols are safe to use on a ketogenic diet, but use them with caution as they may cause gastrointestinal issues such as bloating and diarrhea.
How to calculate net carbs
If a food has a nutrition label, calculating net carbs is easy. Take the amount of total carbohydrates and subtract the fiber, along with any sugar alcohols.
At right: chia seeds have 5 grams of total carbohydrates in one serving, but because 4 of them are from fiber, you only need to count 1 gram towards your daily carb total.
For foods without labels, such as fruits and vegetables, a quick internet search will usually tell you the carbohydrate and fiber content. You can also find the net carb content of many fruits and vegetables on my quick carb reference list.