Vein must be from as far north as Inuits in our world, for it to be impossible to grow any grain or vegetables, and raw meat to be the staple dish. Though I don't know if Inuits traditionally ate their meat raw, Maybe they did if there was no firewood. It's just that cooking meat actually allows a human to get more energy out of it. Some nutrients as well, although some other nutrients will be reduced by chemical decomposition when heated.