This is really wrong.
Someone showed me this on Tumblr and I started typing out a reply there but I was running out of room, so I moved it over here.
First, the water was far from pure. Bacteria were around even then!
Second, and more importantly, they DID NOT EXERCISE!
Exercise is literally defined by the quality that it is specifically for health or fitness, i.e. “Activity requiring physical effort, carried out especially to sustain or improve health and fitness.” Basically it has to be in addition to normal duties you carry out during your life. I walk from my desk to the restroom or the kitchen, that's just normal survival travel, NOT EXERCISE!
No one drives to a fast food place, goes inside, stands in line to order their meal, waits around for it, then walks back to the car and goes back home, walking from the car to the dinner table inside and then posts on their fitness tracking system that they just worked out! (Well some people might if they are cheating, but that's not the point here!)
Anything that you do in order to keep living or be comfortable, such as walking to get yourself food or even just to fetch a remote you left across the room, is considered to be part of normal human movement. You are doing something with your body for some reason. This does not count as something done for health or fitness, therefore it is not considered exercise.
That's why it's wrong to say these people got plenty of "exercise", because they were not. THEY WERE NOT COMING HOME FROM A LONG BUFFALO HUNT AND THEN HOPPING ON A TREADMILL!
These primitive people did what they had to do to survive, not to get abs of steel. Try to remember, back then, fat was seen as being the height of society because it meant that you had other people to do they hard labor of catching your dinner for you.
I bet those people sat down and rested whenever they could!
They certainly slept more, from shortly after dusk to an hour or two before sunrise. In the winter, that could be almost twice as much as modern people get.
While their diet isn’t up for much debate in terms of organic, it was certainly free! They didn't have to eat food that was bad for them because it was all they could afford. If you could kill it you could eat it! Imagine how hard that must have been when there was nothing to kill?
Yeah, I’d be happy to switch back to people who want to eat free range and organic having to locate and then murder their dinner.
I don't have any issue with people who want to do all of the things that are listed here. I know the joke "Dead at 35" is meant to rebut the whole argument of going back to the way things "used to be", returning to "Paleo" or whatever. However, when I see it, I just get annoyed that people are missing the point.
Yes, the air quality and the water might have been less polluted. But were you always located conveniently near said water? No, maybe you lived down stream, after grazing and bathing animals and your settlement died out because of infection.
Yes, maybe your food source was free from antibiotics, but it also may not have been where you lived! Your food source could just get up and wander. If you didn't follow it, to some unknown new area, you died from starvation. If you did follow, you could have died from temperature change, or even another group of people!
They probably had such a young average death age because of other factors like malnutrition, disease, misadventure, murder, animal goring, accidents, war; the list is endless. But I'm pretty sure that either way, food, air or water alone were probably not what determined their lifespan.