Net carbs on the label: why the numbers don't add up
You eat the "2g net carb" bar, the "1g net carb" tortilla and the sugar-free chocolate, and the scale stalls anyway. It isn't in your head. The number on the front of the package is often the least reliable thing on it.
"Net carbs" is the brand's math
In the US, the Nutrition Facts panel has to list total carbohydrate, fiber and sugars. It doesn't have to list net carbs, and the FDA doesn't define the term. When a package says "2g net carbs" on the front, the brand did that subtraction itself, and it decided what to subtract.
The usual formula is total carbs minus fiber minus sugar alcohols. The trouble is in what counts.
Not every sugar alcohol is the same
Erythritol passes through you almost untouched and barely moves blood sugar. Maltitol, the sweetener in a lot of sugar-free chocolate and candy, does move it, much more than erythritol. A label that subtracts all of its maltitol is giving you a number that's too low.
Fiber has a similar problem. Some added fibers are partly digested, and people respond to them differently. That's why one person does fine on a keto tortilla and another gets kicked out of ketosis by it.
Recipes aren't safe either
Recipe sites and cookbooks often copy nutrition from somewhere else or never calculate it at all. When we checked a 500-recipe keto cookbook against USDA food data, about 4 in 10 recipes had printed numbers that were off by more than a third, and the book only gave total carbs.
How to check for yourself
- Read the ingredient list, not the front of the box. If maltitol is near the top, don't trust the net carb number.
- Do the subtraction yourself. Take total carbs from the Nutrition Facts panel and subtract fiber. Only subtract sugar alcohols you know are erythritol.
- Cook from whole ingredients when you can. Almond flour, eggs, cheese and vegetables have known numbers. Processed keto products are where the surprises live.
- If you test, test new products. If you check your blood sugar or ketones, try a new product on its own and see what it does to you.
How we calculate ours
Every recipe in MyKetoCravings is calculated from USDA FoodData Central, ingredient line by ingredient line, per serving. Net carbs are total carbs minus fiber minus sugar alcohols, and the sweetener we use is erythritol, so nothing is hiding in the subtraction. A few of the sweets, with the numbers we got:
Instead of bakery chocolate chip cookies
Chewy Chocolate Chip Cookies
Melted butter, a little xanthan gum and a short chill give you crisp edges and a chewy middle. Pull them while the centers still look underdone.
1.9g net carbs57 min4g protein
Instead of bakery cinnamon sugar donuts
Baked Cinnamon Sugar Donuts
Cake donuts baked in a donut pan, then brushed with butter and rolled in cinnamon sweetener while warm. No fryer, and the coating is the part you remember anyway.
2.7g net carbs33 min6g protein
Instead of candy bar
Chocolate Fat Bombs
Cold, rich and chocolate. Keep them in the freezer for when you want candy.
0.6g net carbs15 min0g protein