The answer being that we have almost stopped evolving. There's something going on in our brains, and we exist. To what purpose, I can't say. Nevertheless, we should try and - fancy word for make real - the "sci-fi" visions of colonizing without commercializing other heavenly bodies.
Meditation is a good way of staying fit. I agree completely with Darwin; survival of the fittest makes sense to me. Unfortunately, being "civilized" has taken its toll on us as a species. To counter the degradation the body as a biological being receives, I try and focus whatever "much deep and profound brain things inside my head" on the tasks I want the body to take care of - a nagging headache, for example.
PS: Also, I squeeze every nutrient out of every thing I ingest. :D