Palaeo peoples on the glaciers in the Ice-Age clearly had little access to raw wild herbs. And child mortality in palaeo times was mostly due to infanticide, not because of any unhealthy diets. Infanticide was necessary as mothers could not cope with more than 1 child at a time and had no birth-control other than breastfeeding. Anyway, the point is that skeletons of (healthy) old people in palaeo times have often been found. This regular infanticide(and de facto mass eugenics) is one reason why humans evolved, without it we would all now be just dumb apes.