In the case of an "acute trauma" type death, we modern people rely very heavily on modern medicine. This is where the bulk of our medical efforts should go, because you really can't just let that bone popping out of your arm sit there and heal itself. Same for infant illnesses.

In the case of a "chronic illness" type death, most modern medicines just try to coat the whole situation with prescription-strength pill bandages. We spend billions of dollars to cure symptoms, yet people live in a doped-up misery with these illnesses for decades sometimes. Sure, they haven't died from the specific disease, but they have all those pesky side effects, for which they take yet more pills. Just look at the name: Chronic (persisting for a long time or constantly recurring). The whole reason these things are called chronic diseases is because they manifest and then they linger. They build and build until you kick the bucket. If you're doing things wrong. We would have to check for the precursors (or just cursors) for these diseases in the remains of the people we know to be well past their 40s. (If we assume an average lifespan of 30 and that infant mortality is very high, then that means there's a good portion of people living past 40, too)

Mark Sisson recently wrote a fairly good summary of a study(pdf) that looked at several different cultures. The take-away, as he puts it:

"This data shows that human longevity is not a product of modern living. It shows that we have inherent proclivities toward long life, as long as we satisfy certain criteria – namely, the steady acquisition of food and shelter and the avoidance of infection, trauma, illness, and violent injury. The evolutionary lifestyle that eschews modern industrial processed food and promotes healthy levels of activity is the same one that supported our evolution into long-living Homo sapiens. Modern technology, sanitation, and medical advances are merely the cherries on top of an already solid framework."

There is also some research (I can't find it right this second) that looked at mummified Egyptians (neolithic diet, mind you) which showed signs of our classic auto-immune diseases, yet never showed signs of cancers. Perhaps we have several tiers of chronic illness resulting from many different layers of our modern lifestyle.

Also, why would we have an increase in auto-immune disorders and a drop in skeletal stature with the advent of agriculture? If we were just plugging along as a race, making steady medical advances throughout our transition from paleolithic to modern, shouldn't we see health increasing proportionally? We do to an extent, but I believe this is just our ability to solve acute problems -- overshadowing the presence of chronic problems. Largely, we have only gained the ability to solve the acute manifestations of chronic problems, so we survive just a little bit longer. That's backwards, but it makes people money, so we're stuck with it on an institutional level.

Comparing modern <30 year olds to our ancestors is also interesting. I've seen children with cancer. I've also seen TONS of <30y/os with auto-immune disorders. I had a friend with completely unexplainable gut problems. After a year, doctors still couldn't pin it down. They didn't even want to say it was IBS, their usual catch-all. Diabetes is creeping younger and younger and is certainly one of those illnesses that can "select" you out of the gene pool if you don't keep on top of the "acute" problems.

For me, there's so much going on with "lifespan" that I would much rather just look at the science. We know the biochemistry mechanisms of gluten and lectins. We can see how they interact with our gut lining. These things have been studied, and the conclusions don't look so tasty.

Ok. Off to buy some grassfed beef liver/meat and raw milk. Cheers!

That 30 year average life span for Paleo men probably includes the number of relatively young men who died in war, or by murder.

As many as one in four Paleo men died in war or by murder - often in their late teens or early twenties. The murders were often over women or theft. I have no idea how they determine this, but that is what some archaeologists and anthropologists say. Bones show the trauma of violent murder from blunt instruments.

A couple of good books that debunk the myth of the peaceful noble savage:

Constant Battles, by Steven A LeBlanc

War Before Civilization, Lawrence H Keeley.

Gurven and Kaplan (2007) argue that lifespan for hunter-gatherers who made it to maturity (e.g. to reproductive age and past childhood illnesses) lived 68-78 years. I believe Mark Sisson discussed the findings of this paper at length a while ago. I can't see much about modernity that would increase the innate genetic lifespan of a human. Being able to treat infectious disease, being protected from trauma, being protected from extreme environments, and being protected from famine all serve to increase the proportion of the population that makes it to the average maximum human lifespan. I'm sure those things also explain a lot about why we can live into and past our 80s. Besides a few genetic freaks like Jack Lallane, most 70+ year olds, no matter how good their diet and health are going to get picked off by a leopard, or get killed in intertribal warfare. So yeah, we can probably surpass Paleolithic maximum lifespans just by having relatively protected lives.

But I don't see anything out there besides the above "protection" hypothesis that would explain why we'd have a longer maximum lifespan than someone 10,000 or 50,000 years ago. We know there is an absence of diseases of civilization in hunter-gatherers, I don't think many people question that. So it isn't like they hit 35 and just dropped dead of a myocardial infarc or their bodies were wrecked by diabetes. If they had good luck, there isn't any reason they wouldn't have made it 6 decades. But living in the wild is hard. They lived in unpredictable environments. A year of bad weather could make food scarce, everyone would be starving, and then they get knocked off by disease.

Immunization, sanitation, the modern food supply chain, housing, antibiotics--these remove a lot of the luck element out of survival (and also allow weaker genotypes to persist). Modern medicine is great at saving victims of trauma, it has varying degrees of success in treating rare genetic ailments that would have taken people out, and again, in treating infectious disease. All that is going to allow more people to make it to their maximum potential, but it doesn't change (at least not significantly) what that max is. The people who make it 110 now, they were probably out there 50,000 years ago. It is simply that living in an unpredictable environment, accidents happen and without the modern world, you have an accident in the wilderness when you're 65 (like, oh, slipping on ice and breaking bones) and you're toast.

In the end though, the argument is pointless. Until we have game changing breakthroughs in genetic engineering, stem cells, nanobots and the like, most of us are going to make it somewhere between 75 and 85. Maybe a little longer. A few folks might make it to 100+. The question I think most of us are concerned with is that given we have access to the modern world, all else being equal, are we going to have a higher quality of life for longer than someone who is fed on vegetable/seed oils, fructose and grains and is largely sedentary? That is the question we need answered, not whether Grok lived to be 80.

No not many 30 year olds have cancer but it doesn't mean to say they don't have the beginings of this and other diseases, with heart disease particularly you can see markers from very early on in life if you are on the road as it were. Plus I have heard of examples of paleolithic remains that show some did live to their 60s and 70s and from what I know it seems they were pretty disease free too.

I understand what you mean, and I think your question makes perfect sense. I am leery of averages. If you have two people, one of whom dies at the age of 2 and the other who dies at the age of 58, their average life span would be 30 years. But that tells you nothing about why these people died...maybe they both met with accidents. And early childhood diseases carried off so many children back then. Even in the 19th century, childhood mortality was 75% in some cities! That by itself would lower the average life-expectancy, even if alot of people lived to a ripe old age. And heart disease and cancer are (or have been) diseases of old age, as you have pointed out. Generally speaking, I dismiss quotes like you are asking about because they are nonsensical. It seems to me they are written to make headlines, and nothing more.

Here is a link to a study on the Masai people of Africa who follow in their youth a diet similar to paleo, including milk and without vegetables. They have amazing health, at least in their youth with this diet. Alghough this is a pastoralist group their diet and lifestyle is probably similar to the one that many paleolithic men had (except for the milk, plus hunter gatherers did have vegetables and fruit)http://wholehealthsource.blogspot.com/2008/06/masai-and-atherosclerosis.html The life expectancy of a paleolithic man that did reach the age of thirty may have been close to the one of a modern man at thirty. Most of the losses in paleolithic men expected life came from averaging the many deaths of children that suffered from trauma, accidents or infections in their early life.

There are some good references on this post:

http://donmatesz.blogspot.com/2010/02/paleo-life-expectancy.html

Also here:

http://paleodiet.com/life-expectancy.htm

Also here:

http://training.apocryphum.com/2010/10/10/life-expectancy-of-hunter-gatherers-paleolithic-humans/

Many more links if you google "paleo lifespan" but they all seem to be referencing the same materials cited in the links above.

As others have said, average lifespan didn't mean they all died at that age, just that many of them got killed off at an early age due to numerous dangers in their environment. However, scientists can look at skeletons and determine approx age via the way the cranium has developed and fused and they can look at the rest of the skeleton to determine overall health, evidence (or lack thereof) of arthritis, etc. Sometimes a whole body gets mummified or frozen and they can learn much more. So they can see what kind of general condition the older folk were in before they died and sometimes even figure out what probably killed them (broken bones, etc).

As an interesting aside, I just read in the paper a few days ago that scientists expect that soon, for the first time in recent history, the average lifespan of Americans may drop instead of rise. Much of the previous rises was due to improved infant survival techniques and keeping sick people alive longer. However, now with much younger people getting illnesses that used to only exist in older people, they expect that to overbalance any other improvements and lead to lesser average life expectancy.