Firstly, just as some general advice and as a general rule, adding "f*ck" to every other sentence or two does not actually make your argument any more cogent, valid or convincing.
Only if you have a narrow definition of "cause" or "reason", of course. This is because there may be other elements of their lifestyle or genetics that prevents the problems that would otherwise arise from it. I think I generally agree with how you've formulated this, however.
Yes there are other factors, I was trying for a very simple example of what a theory might look like in this regard and why the Masai and Inuit examples disprove that theory.
...and you would be wrong. The chunk of evolutionary theory that deals with this issue is called "Life History Theory". What natural selection is "trying" to do is maximize the number of offspring you are going to have before your likely death.
There are external factors that determine how long you can stay alive, including which other organisms are trying to eat you, how many volcanoes are erupting in the vicinity, what viruses have decided to take up residence in your body and the whole glorious panoply of nasty ways that nature has invented for us to die. Because of physical entropy, your tissues also just eventually wear out.
What natural selection can do with humans and other organisms in this regard depends on the availability of energy (i.e. food). One option is to have a physiology that invests some of your food energy in staving off "wearing out" (and hence you live longer, given external killers are sufficiently limited), but if you do, there is less energy for reproduction. You also need to put off reproducing for a while in your life in order to grow, and use some energy for this. When and how far and how much you do each of these things depends on how much energy you can harvest from the environment, how additional growth or learning improves energy harvest, and how likely you are to die at any given age, among other factors.
The balance between all of these factors does indeed mean that natural selection has essentially "chosen" for humans to have probably about 60 to 70 years of life at most, with a long childhood. Females stop reproducing at 45, possibly to finish raising children who are largely dependent into their late teens (yes, teenagers are pains in the backside even in foraging societies) and partly to help invest in their daughters' costly children. This choice is the result of the complex and unpleasant trade-offs that humans face "in nature".
That said, of course, f*ck nature. No-one has to accept the "natural" plan. Nature sucks rocks through a straw. But you can't expect to f*ck nature by doing what cavemen did.
I don't see anything in your argument that even comes close to suggesting that evolution would in some way choose a cut off date for when humans should stop procreating.
Yes there are outside factors such as tigers, volcanoes, falling off a cliff etc. None of these effect the
process of evolution in any great way. At best the people who can run fast enough from the volcano explosion will likely be genetically gifted at speed and so that will be passed on through evolution. However, evolution doesn't decide that because people might die from a volcano then it's best to cut of procreation at 45 years of age.
At it's most basic a person who lives a longer healthier life is much more likely to produce many healthy offspring than a person who lives a short unhealthy life. That healthy person has much more chance therefore to pass on their genes and thereby effect the evolution of the species. It makes zero logical sense for evolution to evolve out the benefits of a long healthy life in favour of a short unhealthy life.
It also makes zero logical sense to somewhat imbue the process of evolution with any sort of conscious decision making ability that weighs up all these factors and decides roughly 45 years of age is going to be the cut off age for procreation. Evolution is simply a process that at its most basic is effected by the genes that are actually passed on and those are far more likely to be the ones of the healthy long lived person than the unhealthy short lived one.
It would be extraordinary if we evolved to eat cereal grains because the vast majority of wild grains were not really plausible sources of food until agriculture started to selectively breed them.
But this whole idea is just ass-backwards anyway. How does natural selection "select for" people to eat, say, tubers or nuts, and not make them "selected for" eating grains? The biochemical differences between the two once chewed and in the digestive tract are minimal at best. There's a bunch of complex starches, some fiber, a bunch of different proteins and some trace nutrients. The systems that can process one set of stuff allow you to process the others. Do you know of any biochemical systems for handling stuff in tubers, say, that doesn't also handle grains, nuts, seeds, squashes and all the other carb sources?
There's the rub isn't it.
Like you say, natural selection doesn't select for people to eat certain things. Natural selection adapts the body to the things the people are actually eating. Eat lots of grains and natural selection will evolve the body to be able to process and absorb the nutrients from grains and deal with or minimize any potential negative effects. Don't eat lots of grains and natural selection wont evolve the body to be able to do that.
And as we seem to agree, humans haven't been eating grains for very long, from an evolutionary point of view. So it makes little sense to believe that we just magically obtained this ability to process and handle massive quantities of grain.
As for the body being able to process it all the same way because we can process some other things..........well as you point out........."There's a bunch of complex starches, some fiber, a bunch of
different proteins and some trace nutrients"
It's those annoying "different proteins" that mostly pose the problems. In particular the vastly different type of gluten that is now present in wheat.
Citation needed, about 1000 times. There is, as far as I can tell, absolutely no problem with gluten for any normal healthy person. Sure, it is a complex protein that takes some digesting, but it's far from the only one even in so called "ancient" foods. Your body is designed to handle weird protein from all over (it has to, given the crazy variety of foods humans actually eat and have eaten).
Two books that will get you started if you are actually interested....
Wheat belly by William Davis
Grain brain by David Perlmutter and Kristin Loberg
The second in particular is interesting. I will admit that Mr Perlmutter does, in my opinion, oversell the conclusiveness of the evidence. However as far as I can tell his credentials are beyond dispute and he receives no money from any vested interest. Both books contain many citations of many studies.
BTW, the sources of calories (fat, sugar, starch, protein) are nutrients unless you are not an ancient person. Actual "paleo" foods are and absolutely have to be very calorie dense because staying the f*ck alive and not starving to death is the most pressing issue, rather than maximizing, say, folic acid. Calories are only "bad" in the modern world. It amazes me that the guys writing these books manage to so completely fail to understand the core of ancient foraging.
Besides, my favorite cereal grain is oats. No gluten, lots of yummies, very non paleo.
Perhaps I was not clear in my use of the term nutrient poor. I know that fats, protein etc are nutrients. I was referring to them as a poor source of micro-nutrients in comparison to other foods.
It is true that the human body has adapted to seek out calorie dense foods because this leads to a greater chance of not starving to death. However, that does not mean that all calorie dense foods are equal or that the the human body has adapted to be able to process and handle all sources of calorie dense foods. Many things that could be a rich source of calories are just plain poisonous to humans. Do you think we are able to eat them simply because they contain lots of calories? As explained earlier, the fact humans did not eat large quantities of calorie dense grains means it is very likely that we did not evolve to be able to handle such grains even though we are adapted to seek out foods that are calorie dense.
I'm glad to know that oats are your favourite grain but I fail to see what relevance that has to the discussion.
...And yet fructose is one of the most paleo-est of all paleo-y food sources. Your fructivorous primate and mammalian ancestors have been eating that shit and squirreling away necessary fat for the winter/dry season for more millions of years than I can count on all my fingers and toes (I mean, hunted meat protein is a mere babe in comparison - a few hundred thousand years? Pffft.). It absolutely has vast nutritional benefit in the form of calories that allow you to stay the f*ck alive (see above). What you mean is it isn't nutritionally valuable given the need for calorie restriction in modern environments. But then paleo foods often suck in modern environments.
We have been eating it for millions of years and I never claimed it was not paleo. My point was that the body does treat the calories from fructose differently to calories from other sources.
A few things though.
1: Almost anything can be toxic to the body in the right dose. Many things are fine or even beneficial in small quantities but quite toxic in large doses.
2: Whilst we have been eating fruit for millions of years, we have only ever had access to very small quantities of fructose in our diet. The massive intake of fructose in the diet of most "normal people" today is simply not good for you.
3: Most, if not all, paleo literature I have read does not have any problem with fruit consumption in general. Merely in the quantity of consumption of fructose through such things as fruit juice and added sugar.
Anyway, I've had my say and these debates simply go round and round in circles. So I'll exit here. As I said previously, everyone should feel free to eat whatever they like though. It's your life and it's in your best interest to find what works for yourself and stick with it.
