Well, the early contact Inuit were known to heat snow into water and cook food, but that is in modern times:
"Also we came home to [an Inuit] dwelling so heated by the cooking that the temperature would range from 85* to 100*F. or perhaps even higher - more like our idea of a Turkish bath than a warm room. Streams of perspiration would run down our bodies, and the children were kept busy going back and forth with dippers of cold water of which we naturally drank great quantities." -Stefansson, Adventures in Diet,
http://www.biblelife.org/stefansson1.htm "In the Barren Grounds, west of Hudson Bay, some groups used no sea products at all, illuminating their snow houses with burning caribou fat and heating these homes with twig fires." -Peoples and cultures of the American Arctic: Traditional culture,
http://www.britannica.com/EBchecked/topic/33100/Arctic/57875/Traditional-cultureI wonder whether this was true also in Paleo days. I can't think of another way to get water in the heart of winter when everything is frozen and there is little or no sun. Once one is heating snow to make water over burning seal oil or whale blubber or reindeer/caribou fat or twigs, why not try sampling some of the heated fat or cooking some flesh now and then? I can't imagine Stone Agers saying to each other, "No, we must not eat heated meat or fat because it violates dietary dogma and might contain ALEs." They would have eaten anything they found that tasted good and didn't make them ill within a short time. However, I think that the scarcity of fuel and importance of it for light and heat, and difficulty in using fats and oils to cook over would have made them eat raw most of the time--at least during the winter months.
So I still think raw is optimal and I will still eat raw, but I can't imagine Stone Agers not cooking at least some food in cold climates.
Stefansson also mentions drinking cold water in the Arctic with meals. I would imagine that it was ice cold, which would seem to suggest that drinking ice water with meals is OK if not optimal.
"...when I left Herschel Island I returned without reluctance to the Eskimo meals of fish and cold water. It seemed to me that, mentally and physically, I had never been in better health in my life." -Stefansson, Adventures in Diet
Granted, Stefansson was not right about everything. For one thing, I think he exaggerated the amount that Inuits cooked food because of his own preference for meats and fish cooked medium to medium well. Still, these things do make me wonder.
My guess is that this issue was addressed here before, but I searched and found nothing.