This information does not just come from fossil records but also from studying living specimen, who still exist in the world today. The article mention that those people also had time to evolve, but I don't think that is much of a killer argument. Then the question would still remain (speaking of diet, which is only one aspect) why they were able to adapt to their diet and we weren't able to adapt to our diet.
> Then the question would still remain (speaking of diet, which is only one aspect) why they were able to adapt to their diet and we weren't able to adapt to our diet.
I think perhaps the point is that there isn't evidence that we haven't been able to adapt to our diet.
We have certainly adapted to an extent, but not enough yet. Proof: civilization diseases do exist. (Not necessarily all about diet, but general lifestyle compared to traditional societies).
The fact that these diseases exist shows that we haven't adapted to not have them.
