You'll see 'net carbs' splashed across keto and low-carb products, but you won't find it on the official Nutrition Facts panel. Here's what it means and why it's not regulated.
What net carbs tries to capture
The concept behind net carbs is that not all carbohydrate affects blood sugar equally. Fiber isn't digested into glucose, and sugar alcohols are only partly absorbed. 'Net carbs' attempts to estimate the carbs that actually raise blood glucose by subtracting those out.
The formula
The common calculation is:
Fiber is subtracted fully because it passes through undigested. Sugar alcohols are often subtracted at half, because the body absorbs some of them. So a bar with 20g total carbs, 8g fiber, and 4g sugar alcohols would be counted as about 10g net carbs (20 − 8 − 2).
Why the FDA doesn't use it
The FDA does not define or regulate 'net carbs,' which is why it never appears on the official panel — only Total Carbohydrate and its sub-lines do. Because manufacturers calculate net carbs themselves, the term is inconsistent and firmly in marketing territory. Different brands may subtract sugar alcohols differently, or not at all.
How to use it (carefully)
For people managing carbs — especially those with diabetes — the underlying idea is reasonable: fiber-rich carbs affect blood sugar less. But rely on the official Total Carbohydrate and fiber lines, and be skeptical of a low 'net carb' claim that leans heavily on sugar alcohols, which can still cause digestive issues and modest blood-sugar effects.