I would conclude that it's natural - did our ancient ancestors, for millenia, not hunt and gather the minimum they required to survive and rest in between to make best use of their energy? Has it not been revealed recently that our progress in agriculture was more to do with providing the ingredients for beer, than with plumping the masses?
The animal kingdom do the same - get what they need, then rest.
Surely modern man is the opposite of this natural state, expending unnecessary and often extreme amounts of labour simply to satisfy his greed?
Embrace our natural state, I say.

- Shipbuilder

There's nothing so lazy as getting a job and a mortgage and a pension and a family and a car and a bigger TV and a ......... just because that's what everyone else does. Whereas the idle person is in many ways the least lazy because they are constantly thinking about outside-the-box kinda stuff which actually makes their life harder.
I see my idleness as something to be cultivated, but I regard my laziness (which I also have in spades) as something negative to be transmuted into pure idleness. When I'm lazy I always feel that I've missed out on an experience that could have been interesting or enjoyable if I had made the 'effort' to be idle.

- Mark3Ants