It's interesting to note that, as soon as a society transitions from a foraging lifestyle, eating fruits, easily preparable vegetables, and game, to a sedentary agricultural society, their lifespan and health both plummet precipitously. Archaelogical evidence indicates that it hasn't been until the last fifty years or so that average health in First World countries reached their pre-agricultural levels. This is due both to the consumption of grains, poor in protein and other nutrients for their caloric content, and the domestication of animals, from whom we get our epidemic diseases.