The sedentary I speak of is that we don't go out in the field and rake and stack hay to feed the livestock that we have to keep healthy to supply our nutrition or income. We don't have to chop wood to keep warm or sweat away tons of water because there was no air conditioning. I mean we don't have to saddle up the horses or follow behind them with a plow to harrow the fields to plant crops to feed ourselves. Those folks, even in my lifetime, would work out in the fields all day with very few breaks to drink liquids and certainly not the gallon jugs that I have seen so many people take to work with them and drink constantly while in their air conditioned cubical all day.
I know that you are active, in our own way, we all are, but, certainly not to the degree that our ancestors were and if they wanted water they had to hand dig a well to get it. And we are the ones that pay somebody thousands of dollars to come up with a reason why we are all overweight. To be honest, I would much rather be overweight then have to have that type of life style, but, to me it is completely obvious why we are and as much as I would love to blame McDonald's for that, I'm afraid it is a much simpler reason.