1. Paleolithic Diet & The End of Universal Trait Fixation
The Paleolithic was so long - 2.6 million year - that Paleolithic man became highly optimized for the Stone Age environment. In the last 10,000 years,
common
not had time to become widespread
or universal
The historical era has been -
Why We Share a Paleolithic Heritage - The Paleolithic began 2.6 million years ago with the invention of stone tools and ended 10,000 years ago with the invention of agriculture. The Paleolithic lasted a hundred thousand generations and was characterized by small populations, typically, tens or hundreds of thousands; at the end of the Paleolithic the human population was 3 million. The modern era has a large population - 7 billion today - but evolution has had little time, less than five hundred generations, to work its magic.
We can calculate - how long it will take before every possible
mutation appears in some person, somewhere.
Every child has a similar number of mutations - about 175 new point mutations among the 3 billion base pairs of the human genome.
- In the Paleolithic, with 10,000 children per generation, it would have taken 8,000 generations, or 160,000 years, for each possible mutation to occur once.
- Today, with more than a billion children per generation, every possible point mutation now appears about twenty times per generation, or almost yearly.
Every child has a similar number of mutations - about 175 new point mutations among the 3 billion base pairs of the human genome.
This time is on the order of ln(N)/s, where N is the population size and s is the selection coefficient, a measure of how beneficial the mutation is in terms of expected number of children.
- In the Paleolithic, a mutation that raised the probability of having an extra child by only 0.1 percent would have reached fixation in 460,000 years. So a mutation with selective advantage of 0.1 percent would have occurred within the first 160,000 years of the Paleolithic, then become universal 460,000 years later - long before the Paleolithic was over.
- In the modern era, a similar mutation would occur every year but would require 200,000 years to reach fixation. The modern era is less than 10,000 years old, however, so few recently mutated genes have had time to become universal. As a result, our genetic adaptation to the new environment of modern life - agricultural foods, city living, the presence of governments and complex institutions - is incomplete. And human genetic diversity is greater than ever before.
Because mutations that would remove our adaptation to Paleolithic diets have had little time to spread through the population, it is likely that nearly everyone is extremely well adapted to Paleolithic diets. The same cannot be said for modern diets.
References*
1 - Hawks, J. et al., "Recent acceleration of human adaptive evolution," Proceedings of the National Academy of Sciences of the United States of America 104, no. 52 (December 26, 2007): 20753-58, http://pmid.us/18087044.
2 - Nachman, M. W. and S. L. Crowell, "Estimate of the mutation rate per nucleotide in humans," Genetics 156, no. 1 (September 2000): 297-304, http://pmid.us/10978293.
3 - Kimura, M. and T. Ohta, "The average number of generations until fixation of a mutant gene in a finite population," Genetics 61, no. 3 (March 1969): 763-71, http://pmid.us/17248440.
The Perfect Health Diet
http://www.amazon.com/Perfect-Health-Diet-Regain-ebook/dp/B007USA6MM
The 10,000 Year Explosion
http://www.amazon.com/The-000-Year-Explosion-Civilization/dp/0465020429
Evolution's Sweet Tooth
Since sugar is a basic form of energy in food
Simply put, humans evolved to crave sugar, store it and then use it. For millions of years, our cravings and digestive systems were exquisitely balanced because sugar was rare. Apart from honey, most of the foods our hunter-gatherer ancestors ate were no sweeter than a carrot. The invention of farming made starchy foods more abundant, but it wasn’t until very recently that technology made pure sugar bountiful...
https://www.nytimes.com/2012/06/06/opinion/evolutions-sweet-tooth.html
2. Evolved Food Preferences
Consider the survival
problem of what
food to eat.
Humans are faced with a bewildering array of potential objects to ingest—berries, fruit, nuts, meat, dirt, gravel, poisonous plants, twigs, and trees. If we had no taste preferences and ingested objects from our environment at random, some people, by chance alone, would consume ripe fruit, fresh nuts, and other objects that provide caloric and nutritive sustenance. Others, also by chance alone, would eat rancid meat, rotten fruit, and toxins. Earlier humans who preferred nutritious objects survived.
Our actual food preferences bear out this evolutionary process. We show great fondness for substances rich in fat, sugar, protein, and salt and an aversion to substances that are bitter, sour, and toxic. These food preferences solve a basic problem of survival. We carry them with us today precisely because they solved critical adaptive problems for our ancestors.
Our desires in a mate serve analogous adaptive purposes...
...Although ancestral selection pressures are responsible for creating the mating strategies we use today, our current conditions differ from the historical conditions under which those strategies evolved.
Ancestral people got their vegetables from gathering and their meat from hunting, whereas modern people get their food from supermarkets and restaurants.
Similarly, modern urban people today deploy their mating strategies in singles bars, at parties, through computer networks, and by means of dating services rather than on the savanna, in protected caves, or around primitive campfires.
Whereas modern conditions of mating differ from ancestral conditions, the same sexual strategies operate with unbridled force. Our evolved psychology of mating remains. It is the only mating psychology we have; it just gets played out in a modern environment.
To illustrate, look at the foods consumed in massive quantities at fast food chains. We have not evolved any genes for McDonalds, but the foods we eat there reveal the ancestral strategies for survival we carry with us today. We consume in vast quantities fat, sugar, protein, and salt in the form of burgers, shakes, french fries, and pizzas. Fast food chains are popular precisely because they serve these elements in concentrated quantities. They reveal the food preferences that evolved in a past environment of scarcity. Today, however, we over-consume these elements because of their evolutionarily unprecedented abundance, and the old survival strategies now hurt our health. We are stuck with the taste preferences that evolved under different conditions, because evolution works on a time scale too slow to keep up with the radical changes of the past several hundred years. Although we cannot go back in time and observe directly what those ancestral conditions were, our current taste preferences, like our fear of snakes and our fondness for children, provide a window for viewing what those conditions must have been. We carry with us equipment that was designed for an ancient world.
Our evolved mating strategies, just like our survival strategies, may be currently maladaptive in the currencies of survival and reproduction. The advent of AIDS, for example, renders casual sex far more dangerous to survival than it ever was under ancestral conditions...
https://labs.la.utexas.edu/buss/
The Evolution of Desire:
Strategies of Human Mating
by David M. Buss
http://www.amazon.com/exec/obidos/tg/detail/-/0465021433/
