Paper has calories. Calories are a measurement of heat given off when a burnable substance burns, so anything that can burn has calories.
But our bodies don't burn fiber. We'd starve to death on a diet of paper, because we can't access the calories in cellulose (dietary fiber).
So why aren't more calorie counting resources (aimed at humans) subtracting the fiber calories from the calorie counts?
Today I looked up the calorie count for cabbage calories on several popular calorie counting sites and found that they all overestimated calorie content by 100%. The useable calories amounted to half what the counters list.
In the USA, on nutrition labels and in calorie counting resources, it is permissable but not required to subtract fiber calories from the calorie total.
It really ticks me off, because it makes vegetables and fruits appear higher in calorie than they actually are.
Resistant starch, inulin, and sugar alcohols are another source of undigestible carbs. I get though why those calories aren't always subtracted. There's some evidence that the ability to digest these carbs may vary (so food containing them may provide me with more or fewer calories than they provide you)...
... but NO human being can digest fiber, so why are they still being counted for dietary purposes?
Ok, end of rant.