A "keto" snack pack prints in huge letters on the front: "Only 3g net carbs".
Flip it over, and the nutrition table says carbohydrate 15g. So where did the other 12g go?
Nobody is lying. The two numbers are just counting two different things. And the root of it all is one small line on the label: fiber.
In this article
Fiber is the carb your small intestine cannot crack
Dietary fiber belongs to the carbohydrate group, in the same family as starch and sugars. The difference is that human digestive enzymes cannot cut it apart.
So fiber passes through the small intestine almost intact. In the large intestine, some of it becomes food for friendly bacteria. They ferment the fiber and produce a little energy for your body.
That is why fiber still has calories, but not many: about 2 kcal per gram, half as much as starch.
Two kinds of fiber come up often:
- Soluble fiber: turns thick and gel-like in water. Found in oats, beans and many fruits.
- Insoluble fiber: keeps its shape, helping stools stay soft and regular. Found in seed husks and leafy greens.
The US counts it in, Europe keeps it apart
Here is a fun fact few people know. The same word, "carbohydrate", means different things in different places:
| US-style label | European-style label | |
|---|---|---|
| Carbohydrate line | Includes fiber | Excludes fiber |
| Where fiber goes | A child line, indented under carbs | Its own line, at the same level |
So for the same snack pack, a US label might show carbs 15g, of which fiber 12g. A European label would show carbs 3g and fiber 12g, as two separate lines.
And labels in Vietnam? The international Codex guidelines allow both approaches, so you need to look at the layout:
- Fiber indented under carbs, written "of which fiber": carbs usually include fiber.
- Fiber on its own line at the same level: carbs may not include fiber.
If you are not sure, try adding up the calories yourself. The article on what is a calorie shows you how.
Net carbs are a subtraction, not a regulation
Net carbs are a popular way of counting on low-carb diet foods:
Net carbs = Total carbs − Fiber
Some products also subtract sugar alcohols such as erythritol, because they give very few or almost no calories.
The key point: in the US, "net carbs" is not a term defined by the regulator. Each brand may subtract its own way. Two packs both saying "5g net carbs" may not be calculated the same way.
A few things to remember when you see the words net carbs:
- Low net carbs does not mean low calories. Many keto snacks use almond flour, butter and coconut oil. Few carbs but plenty of fat, and fat gives 9 kcal per gram.
- Always read the energy line too. It tells the overall story and is not affected by how anything is subtracted.
- Added fiber is not the same as fiber in whole grains. Some products add isolated fiber like inulin to bring net carbs down. It is still real fiber, but it does not come with the vitamins and minerals of whole grains.
How much fiber do you need a day?
WHO recommends adults eat at least 25g of fiber a day, from naturally occurring sources in food.
That does not sound like much, but picture it (figures from USDA):
| Food | Fiber (approx.) |
|---|---|
| 100g cooked chickpeas | 7 to 8g |
| 100g guava | about 5g |
| 100g dry rolled oats | about 10g |
| 100g white rice | under 1g |
A day of only white rice, meat and a few vegetables makes 25g very hard to reach. Add a bowl of beans, a few slices of guava and a handful of oats at breakfast, and it is a different picture.
When reading labels, fiber is one of the rare lines you want high. Under Codex guidelines on nutrition claims, a product with 3g of fiber or more per 100g can be called a "source of fiber", and one with 6g or more can be called "high in fiber".
Inside the kOBE kitchen
kOBE Signature Monk Fruit Blend has five ingredients: erythritol, allulose, monk fruit, stevia and inulin.
Of these, inulin is a type of fiber and does not sweeten. Erythritol is the sweet base and gives bulk. These are exactly the two kinds of ingredients that often make the two carb numbers on a label differ: one is fiber, the other a sugar alcohol. Next time you read the label on any jar of sugar alternative, you will know why total carbs and net carbs can be far apart.
The blend replaces sugar 1:1, so however many spoonfuls of sugar an old recipe calls for, you use the same number of spoonfuls. See kOBE Signature Monk Fruit Blend.
Frequently asked questions
Does fiber have calories?
Are net carbs an official part of the label?
Can a fiber powder replace vegetables?
Keep reading
Sources
- WHO (2023). Carbohydrate intake for adults and children: WHO guideline.
- U.S. FDA. 21 CFR 101.9, Nutrition labeling of food (total carbohydrate includes fiber).
- European Union. Regulation (EU) No 1169/2011 (carbohydrate and fiber declared separately).
- Codex Alimentarius. Guidelines for Use of Nutrition and Health Claims (CXG 23-1997).
- USDA FoodData Central: cooked chickpeas, guava, oats, white rice.
- Further reading: Understanding Nutrition 16th ed., chapter 4.
