Do you subtract fibre from carbs? Read a label and see

"Net carbs" means total carbohydrate minus fibre, but whether you should subtract anything depends on your label. On US-style labels the total includes fibre. On EU and UK labels fibre is listed on its own line and is already left out of the carbohydrate figure.

Pick a food, switch label style and see what to count, and why subtracting twice goes wrong. Not medical advice.