The ability to do rapid analysis of the genome has radically changed our understanding of human genetics over the past 10 years, and the consensus is evolving (no pun intended). It is becoming clear that evolution continues unabated, even though arguable the neolithic revolution allowed a higher percentage of children to reach reproductive age and then reproduce (although those of us who have adopted the Paleo lifestyle would argue they are less healthy throughout their lives.)

As others have written, changes such as blue eyes are relatively recent. Light skin, while pre-dating agriculture, is something that probably evolved within the past 30K years, and interesting was a mutation that happened independently among Indo-European and East Asian populations. (strong evidence that we desperately need sun exposure). Adult lactic tolerance is very recent, and post-agricultural.

It is pretty evident that populations rapidly adapt to their environment. Compare the average physical structure of a person from Siberia to someone from the tropics. Or someone from a high altitude region to a lowlander. It seems to only take a few hundred years for those changes to manifest.

The percent of the genome that has changed is irrelevant. I laugh whenever someone points out that we share 96% of our genes with chimpanzees. We are 85% similar to mice. So what. It's the small differences that matter.

For anyone interested in population genetics and genetic anthropology, there is a pretty good blog called gene expression: www.gnxp.com

The evolutionary premise is only used for explanation of the diet after it corroborates hard empirical evidence. However it is pulled out of context by some who then go on to use the evolutionary premise standalone, and then you can see gaps in it.

The simple fact is that we only draw evolutionarily correlations because they look nice. The fact of the matter is that we understand way more about our current selves than we ever will about our ancestors. That current understanding forms the foundation of the science behind the diet. The evolutionary argument comes a fortiori from the medical science.

http://healthcorrelator.blogspot.com/2010/01/how-long-does-it-take-for-food-related.html

This might help.

Blue eyes are only 5,000 yrs old so yes we are still evolving. The thing with genes is that although they spread we all don't have blue eyes. Think of this as your body's adaptation to certain foods. Some have the new mutation but it's internal and you can't see whether or not you do. So why gamble? Feel better now and avoid all foods that we would have had to evolve to be able to handle and you'll also benefit in the future by bypassing the diseases that these foods can bring on (if you don't happen to have the new adaptation). Same with smoking, some can smoke their whole life and never get cancer, others can smoke and get cancer within a year or two. Why take the well documented risk? You're playing Russian roulette with your genes with these Neolithic foods. I choose not to gamble if I've inherited the newer adaptations to them or not (plus just like cigarettes I feel better now if I avoid them.)

Edit, not trying to say blue eyes are any better than another eye color just trying to point out that all gene mutations do not spread uniformly across all populations/I do not have blue eyes.

The fact that humans cannot thrive on grains and sugars should be enough validation of the premise. We are not birds, rodents, or bees.

Personally, I think evolution can happen rapidly under the right circumstances and food availability is one of those circumstances. However, food types have changed to an extreme extent over just the last 100 years. That combined with the very recent modern conveniences that make our lives easier, but also take away a large portion of the survival of the fittest pressure, probably makes it unlikely we have had time to adapt to the current SAD diet, not to mention potential issues with current levels of brand new GMO type foods and chemicals permeating the environment.

Also, considering that most of the SAD diet problems, at least up until recently, were not fully developing until the latter end of the reproductive years, this probably also has slowed down evolution to the current diet. However, it seems now that the spiral of fructose/sugar/carb addiction and consumption is actually escalating so rapidly that even many highschoolers are starting to suffer from diabetes and fatty liver disease and fertility is rapidly dropping in westernized countries, the rate of evolution may soon start to pick up. However, too late for those of us already born and surviving. We are stuck with the genetics we already have and better learn to deal with it if we know what is good for us. -Eva

The short answer seems to be that we are changing faster than ever before, but not enough to reverse all of our previous evolution and to make agricultural diets healthy for us. At most, some genetic groups may have adapted in order to tolerate them better. This gets into the new field of nutrigenetics.

My recent pet theory is that among jews (one of the most studied genetic groups) Middle Eastern Mizrahi Jews have adapted relatively more in order to tolerate grains and beans, ie Mediterranean diet; whereas European Ashkenazi Jews have adapted less and have more to gain by a more strict Paleo diet.

Any thoughts?

I read John Hawks blog and I believe he is correct -- humans actually are changing genes significantly. Stephan at wholehealthsource and I have discussed that actually a lot of evidence now exists that humans are de-evolving. Our cranial size has shrink 17% in the last 100 yrs alone. wtf!

Evolutionary medicine may explain these changes. Dr. Wallace is big on studying the female lineage of DNA transer, eg mitochondrial DNA (mtDNA). He believes that within a human's lifetime, mtDNA, accumulates mutations which lead to shortened lifespan, chronic conditions and increased ROS and thus aging. Mitochondrial DNA mutations in disease and aging. Wallace DC. Environ Mol Mutagen. 2010 Jun;51(5):440-50. Review. Colloquium paper: bioenergetics, the origins of complexity, and the ascent of man. Wallace DC. Proc Natl Acad Sci U S A. 2010 May 11;107 Suppl 2:8947-53.

I believe Wallace is correct (and thus both Cordain and him are correct IMHO). the nuclear DNA (nDNA) may indeed have little changes however our metabolism, enzyme pathways are entirely dominated by mitochondrial processes. When the mtDNA is changing and mutating to adapt to ecological microniches, what is happening to the epi-genome? We are are in fact changing it.

Barry Groves discussing very eloquently how what our GRANDPARENTS ate, determines our health and longevity!

BTW -- I think only eating an evo/paleo styled diet and moving intensely and low intensity for durations is the ONLY way to reverse these mtDNA mutations AND the epigenetic changes.

Fish oil ingestion has been shown in mice epigenetic studies to reverse maternal epigenome damage on hypertension.

-G

The important thing is that the metabolic and genetic pathways which exist within our body are very old. And practicing a paleo lifestyle through diet, infrequent but intense exercise, and intermittent fasting are beneficial in nurturing these pathways.