Keto bread can have zero "net carbs", but the total carb count is not really zero.  We get the "net carb" amount by subtracting the fiber content from the total amount of carbohydrates.  That's because your body doesn't process fiber or get any energy from it.  So while some low carb loaves of bread may have the same amount of carbs as traditional bread, if it has high enough fiber content, then it can be considered Keto.