I don't get it. 
We used to be animals. We didn't know destilation of water or heating of the meat. Since then, I don't thing we could have possibly changed so much biologically.
Even if we count child bearing at the age of 15 and another 13 years of defending kids, That would put minimal required survivor age at 28.
How is it possible, that unfiltered water and raw meat can kill us now? And is that shit reversable?
@LukeAlmighty You can ingest raw/unfiltered whatever and unless there's bacteria in it, you'll be fine. It's just that digestion is easier and more efficient (more calories extracted) from cooked food. Aside from killing parasites, cooking partially breaks down the matter in the food (plant or animal), so an advantage is to be had by doing so: in nature, the more efficient user of calories tends to be the one that survives.
@Aurelius_17_6_313
>Unless there's bacteria.
Ouf... so I just have to find a disinfected water... how hard could that be anyway.
Sorry for my sarcasm, but that was exactly my point.
@LukeAlmighty Not hard. In general, moving water is typically going to be clean, still water not so much. Drink from springs and streams, not from ponds and lakes. If the latter are your only options, get it boiling for at least one minute (three at high elevation, 6k and up iirc).