While roots and berries are capable of sustaining any individual for a long time, its no real replacement for those who lust after the taste of flesh. The wilderness is inhabited by many creatures, whose flesh is very edible. Catching these creatures is a challenge indeed however. The best way to catch these types of creatures is to trap them. Most of the time they are fleet of foot and cannot be simply caught and killed with a sword. Simple rope traps, and other means allow one to catch his prey, easily and cleanly. A skilled hunter can live forever on his own. Of course once the prey is caught preparing it is another task, maybe if you could cook it over an open fire...