How To Calculate Net Carbs for Low Carb & Keto Diets

Since July 2018, when I started on my Keto journey, I have maintained 20 net carbs or less per day. Usually much less as I use good fats instead of carbs to keep me satisfied. Once you get in the habit of checking labels and researching carb counts you’ll just automatically know what’s good for you versus what you should avoid.

On any low-carb diet, you will be reducing your net carb gram intake. It is important that you understand how to actually count net carbs. First, net carbs are simply the grams of total carbohydrates in a portion of food minus its grams of fiber. Because fiber is a carbohydrate that your body cannot digest, it does not raise your blood sugar levels or trigger an insulin response.

Foods that are low in net carbs, which include nutrient-dense vegetables and fruits, are less likely to interfere with weight loss and do not have a significant impact on blood sugar.

Here are a few zero- and low-carb foods to help you get started on understanding why they are often listed as acceptable foods in low-carb diets:

Examples of Zero Carbs

Beef
Lamb
Chicken
Pork
Bacon (but avoid the bacon cured in sugar)
Salmon
Trout

Examples of Low Carb Vegetables

Broccoli – 6 grams per cup or 7 grams per 100 grams.
Tomatoes – 7 grams in a large tomato, or 4 grams per 100 grams.
Onions – 11 grams per cup or 9 grams per 100 grams.
Brussels Sprouts – 6 grams per half-cup, or 7 grams per 100 grams.
Cauliflower – 5 grams per cup and 5 grams per 100 grams.
Kale – 7 grams per cup or 10 grams per 100 grams.
Cucumber – 2 grams per half-cup or 4 grams per 100 grams.

Examples of Low Carb Fruits

Be careful, as you can see fruits are higher in carbs than vegetables due to their sugar content. Since starting on Keto I very rarely eat fruits, except for avocados and occasionally berries.

Strawberries – 11 grams per cup or 8 grams per 100 grams.
Apricots – 8 grams in 2 apricots, or 11 grams per 100 grams.
Avocado – 13 grams per cup or 8.5 grams per 100 grams.
Grapefruit – 13 grams in a half grapefruit, or 11 grams per 100 grams.

How to Calculate Net Carbs

You can calculate, for yourself, the approximate number of net carb grams in a low-carb product. First look at the information on the food label:

Total Carbohydrates
– Dietary Fiber
– Sugar alcohol
= Net carbs

Often, the food label will break down carbohydrates into total carbohydrates, fiber, and sugars.

Total carbohydrates combine all of the carbs and include fiber, sugars, starches, sugar alcohols and glycerin. The label will show the amount found per serving and is measured in grams. They are found in starches, vegetables, fruits, sweets, and milk.

Dietary fiber is the amount of indigestible or partially digestible bulk from plant foods like fruits, vegetables, whole grains, oats, nuts and seeds and is measured in grams.

Sugar alcohols are found most often in foods labeled “sugar-free,” including candy, cookies, chewing gums, and soda, but have recently become popular in packaged health foods. Sugar alcohol gets its name from its molecular structure, which is a hybrid between a sugar molecule and an alcohol molecule. Biochemically speaking, sugar alcohols are structurally similar to sugar but are either poorly digested or poorly metabolized.

Sugar alcohol has grown in popularity as a sugar replacement in foods because they contain few calories, have a minimal impact on insulin levels, and are safe for those with diabetes.

Here’s a list of some popular sugar alcohols so you can identify them when you look at a nutrition label (*note: the only one of these that I personally use with Keto is Erythritol. I try to avoid the others.):

Erythritol
Maltitol
Hydrogenated starch hydrolysates
Isomalt
Lactitol
Mannitol
Sorbitol
Xylitol

It can be confusing, at first, when trying to calculate net carbs on your own, but now that you have the basic information you can practice it at home first. Soon you will be confident in your ability to count net carbs during your next trip to the grocery store.

I also recommend the Carb Manager app available on your phone (iPhone and Android) to keep track of your carbs or to at least help you figure out your net carbs – because it does the work for you.