[bane]

It's relatively easy to test though. You can look at life expectancy figures of hunter gathering cultures (which are a useful proxy for pre-agricultural cultures) that don't deal with modern issues, or didn't deal with them at some point that we have pretty good data on. For example the life expectancy in Papau new Guinea was flat lined at just over 30 until about 1940.

You can see similar trends in other non-agrarian societies.

http://www.gapminder.org/world/#$majorMode=chart$is;shi=t;ly...,

There are studies that go along with your POV

http://www.anth.ucsb.edu/faculty/gurven/papers/GurvenKaplan2...

but they are, to date, very much in the minority of research in the area.

[ubercore]

Doesn't infant mortality greatly skew life expectancy? I thought I remembered reading that it's the single biggest thing we've done to increase life expectancy, meaning if a hunter-gatherer reaches adulthood, they don't have an especially short lifespan compared to a developed country.

[bane]

Absolutely. But the premise we're testing here essentially boils down to "we should do things like cavemen because it's natural, because it's natural it's what we evolved to do, since it's what we evolve to do it'll be healthier"

The other component of that is of course that we're all fat and out of shape today because we eat foods that cavemen never had access to.

One measure of health is of course weight, but so is life expectancy. If we follow a life-plan where we're around some normal weight but die at 30 I'm not sure that's a great plan. We evolved to die around 30, most research into aging agrees with this (some say ~40), and that's "natural" I suppose, but I think I reject that notion that we should only do things in the modern world that fit what we were required to do a million years ago because it's what we evolved to cope with and eek out 3 or 4 decades of life.

Another is infant mortality, we evolved to reproduce pretty fast because we evolved to maintain population with lots of dead infants. We also evolved to produce slightly more males than females since men die faster, which is okay since fewer men can reproduce with more women.

We also evolved to be able to bear children in our early teens, to grow beards, hair and nails, and to have bad eyesight in some large percentage of the population. Should we lower the age of consent to 13? Not shave or cut our hair or nails ever and not wear glasses?

I'm not sure any of these notions work today, but extending the central argument out:

If we should eat like our ancient ancestors did since we evolved to eat like that and therefore it must be healthy, should we not live like our ancient ancestors did since therefore that must be equally valid by the "it's all natural so it's good" principle?

[ubercore]

I think you're missing my point: if it's infant mortality that keeps average life expectancy down, it's false to say that "caveman" diets are optimized for only aging to 30. I think it's closer to the truth to say that cavemen either died at birth, or lived a natural lifespan closer to modern man than an average would indicate. So you can't discount a "caveman" diet because average life expectancy was (and in some cultures still is) 30 years old.

And I think it's a straw man to say that accepting a "caveman" or "hunter gatherer" diet means we need to accept -every- aspect of "primitive" life.

EDIT: http://www.anth.ucsb.edu/faculty/gurven/papers/pdrdraft04182...

[bane]

Even if there is a 0% infant mortality rate, if everybody dies around 30, the average life expectancy can still be 30. Like I said, this is easy to test, there are still quite a few hunter gatherer cultures around, and they aren't exactly struggling to deal with an elderly care problem. This is pretty well studied. What you are supplying is conjecture, or perhaps an interesting hypothesis.

"I think it's closer to the truth to say that cavemen...lived a natural lifespan closer to modern man." Test it! I honestly don't know the answer, the data I managed to find in 10 minutes of searching says that hypothesis is incorrect -- but as you rightly point out my data includes infant mortality in the averages (I believe). But if you can find data that says "excluding infant mortality, pre-agrarian cultures have an average lifespan of 70-80 years" I'll be more than happy to accept that.

http://en.wikipedia.org/wiki/Life_expectancy

According to the entry above, there's a measure called e5 that should supply the relevant figures.

And I think it's a straw man to say that accepting a "caveman" or "hunter gatherer" diet means we need to accept -every- aspect of "primitive" life.

I'm not really attacking the diet per se, many of the recipes are actually pretty tasty and are generally pretty healthy. I'm attacking the faulty line of reasoning given as to why one should do this.

"it seems to be pretty healthy" is wishy washy, but okay

"You should eat this way because evolution made you to eat this way therefore it's healthy" is not, it present a long chain of reasoning that falls apart at almost every link, but it's presented as a kind of science, which it's not by this reasoning.