David Reich

group of people in Europe and the Middle East over the last 10,000 years has moved into a period of relatively more stable food where building up stores of fat are not as advantageous and there's been selection against this combination of traits.

Europeans actually are relatively better protected

genetically against type 2 diabetes than some other populations around the world, like African-Americans and Native Americans that have perhaps not been as exposed to agriculture for as much time.

So you may be seeing the effect of more exposure to more stable food accessibility.

I think there's a timescale issue.

You're absolutely right.

So I think, as I understand, and I'm no anthropologist, but my understanding is that when there's a hunt in some of these traditional societies or communities that hunt, people will often gorge themselves and eat a huge amount.

and build up a sort of temporary store of fat and then go with multiple days without eating meat sometimes until the next hunt.

And so there is this sort of boom bust access to high value nutrition that is not true to the same extent in farming communities.

On the flip side of this, these long, these famines are, I think, something that occurs more commonly in agricultural societies, but the timescale and the tempo of them is very different from the hunting tempo.

So maybe there's a famine every three years.

And indeed, if you look at the bones of farmers, at least in some communities, there's more stress in them, maybe due to a famine every three years or a famine every five years.

But selection might not be acting on that three-year time period.

Your fat store from the latest hunt is not going to carry you through to the famine three years later.

And so survival of famines is a different thing than building up body fat for being able to survive

two weeks later.

We have lots of energy to spend on it, right?

I think there's more room at the top for a lot of these traits.

I think that you can move height very extremely in one direction much more than it is today.

You can move any of these traits very much more extreme in the other traits.