Nobody is saying we didn't evolve. Humans have definitely evolved in the past few thousand years, and there are definite adaptations that you can see in terms of dairy and other food tolerances that some groups have.

What is increasingly clear is that many humans have not adapted very well to cereal grains, especially wheat. And the amount of omega-6 fatty acids that most humans consume today is well outside of our evolutionary experience, and has only been going on for about 100 years. Sugar consumption has also increased dramatically in the last few hundred years. The amount of time that people spend indoors, sitting in chairs, driving, wearing fancy athletic shoes, etc., has probably increased dramatically in the last few hundred years or in the past few decades.

If you read the full text of the article, only the fishes living in one portion of that pool were selected to become resistant to the to lime-barbasco compound released into the stream by the natives. Fishes in other parts of the underground stream still exhibited no resistance to the toxin, and even the fishes who were more tolerant of the adverse conditions would still die if they were exposed to the elevated concentrations of the compound laden water. They just lived long enough to wait out the natives.

Translating this to humans - it's apparent that many humans have adapted to utilize lactose, gluten, and other food sources. The problem is, many of us haven't been selected to tolerate diets high in those compounds, particularly those of us who's ethnic backgrounds can't be traced back to wheat or dairy consuming regions. Also, none of us are well suited for the contemporary calorie rich, carbohydrate dense, sugar laden, low fiber diets. Thats why we are seeing metabolic disorders spiraling out of control in developed nations .

Ivan,

You need to do some reading. One place to start would be the 10,000 Year Explosion.

[Response to Jae above:]

I just said that the topic was important because it seems to be one of the most conspicuous of the fruitful areas of disagreement on this site. We all agree on certain basic principles; the leftover stuff we enjoy debating often falls within this topic. (And we enjoy debating it a lot, judging by the number of times variants on the question come up.) Anyhow the simplest way to put the question is: How much genetic (or epigenetic, whatever) change has really taken place? And people take different sides. Patrik for example is generally on the "more change" side of things. (I somehow think Patrik won't mind being the victim of gross oversimplification here, sorry Patrik.) I used to be on the "less change" side of things but am coming around a little bit. In fact it was because of reading threads on this site and giving tentative answers that I decided to take a retirement from the topic to go read a textbook on genetics. (And then come back and prove everyone wrong for all eternity learn more.)

So I think maybe you are saying that we get a primary evolutionary result and then we tinker with individual situations after we have that. But I think that there are three things going on, not two: one, the primary evolutionary result, three, the individual tinkering, and then in between is two, whatever we can learn about genetics since the beginning of widespread agriculture. We already know that there are some convincing genetic finds that are relevant to the discussion: lactose tolerance, skin color and vitamin D, alcohol tolerance. And I know that you of course are aware of these things. So then the question is: what else can we find? I mean, maybe we'll just find that we can't find any helpful patterns with any reliable degree of certainty that apply to the question of evolution since 10,000 years ago, and then it really would in the end boil down to the two-fold situation instead of the three-fold situation: we'd have the main evolutionary result and then beyond that just the individual tinkering. But we at least have to reach that conclusion first.

Sorry if I'm belaboring something unrelated to your question. You can just let me know where we're missing each other if you want. Paul.

You have to consider lifespan and the strength of the selection effect. Fish don't live long (= lots of generations) and the penalty for not being adapted was death. Humans do live a long time (= few generations) and grains rarely kill us before we reproduce. So the selection effect is not nearly as strong.

A good question, but we are significantly more complex organisms than these fish. In addition, we have knowledge of genetics and the alleles that coincide with gluten intolerance...

99.6% of humans are intolerant at some level... So to that I say , nope we haven't evolved to it yet.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842922/

I say yet because we haven't had this access ti this quantity of gluten until very recently. Humans may eventually adapt.

We are so widespread nowadays that a mutation would be incredibly slow to spread thru the entire population.