The article touches on this, but doesn't directly address it: whether they're using gross calories or net calories. Gross is the total calories you burn during

The article touches on this, but doesn't directly address it: whether they're using gross calories or net calories. Gross is the total calories you burn during that mile. Net is how many additional calories you are burning as a result of walking versus being sedentary. Glancing at the wikipedia article which the author uses doesn't clarify this, nor does Wikipedia's citation. I didn't check the citation's citation. Clearly we want net calories. Average humans burn ~100 kcal per hour doing their normal activities during the day, so that could potential change the figure from 210 kcal per hour walking, to 110.