Our bodies evolved to stay alive long enough for our kids to have kids of their own, somewhere between 30 and 40ish. There is no grand plan, no set lifestyle that will perfectly suit our bodies. Such concepts tough on quasi-religious ideas of grand designs and lost edens. Evolution is a dirty and unplanned mess of factors without any plan. Brushing my teeth every day isn't something my body evolved to handle. The bit of evolution that gave me wisdom teeth had in fact a very different plan. That doesn't mean I should return to the 'natural' lifestyle of not taking care of my teeth. Sitting too much is no doubt bad for our hearts, but there is no idealized 'balance' between sitting and jogging, a form of exercise that didn't even exist until maybe 1800.