I have very light skin and red hair. My kids have mid range skin, and half their genes come from near the equator. I find it incredible that the pediatrician's recommendations for sun exposure and sunscreen are identical for them as they were for me. Especially since every person in my wife's family who lives far from the equator is vitamin D deficient.

The bit about those who live further north suffering from things more than those closer to the equator was thought provoking.

Access to sugar has increased many-fold over human history. The incidence of sunlight exposure has dropped dramatically.

The reduction of sun exposure is vicious -- for white people, especially pasty-white hackers like me, it can only take a few minutes to burn. So the medical community recommends we stay inside and lather up to stay pasty. And take a "pharmacopoeia" for the resulting depression, hypertension, cancer, reduced disease immunity...

But if I spend time outdoors year-round, my skin takes on an olive tone, my freckles get darker, and when summer comes around I can enjoy the sun without fear of burns. But that's free health care, and the medical industry makes money hand over fist with that pharmacopoeia.

I'm going to give the medical community the benefit of the doubt here, and particularly, the dermatological community. Skin cancer is something in their domain, and so of course it's a big deal for them, but I think they're missing the forest for the trees.

The other side of the argument is that you might not have visible burns, but you are still being exposed to high-energy radiation that will damage the DNA of skin cells, making you more prone to skin cancer. This risk can be somewhat mitigated by going for regular skin checks as you age. All things taken into consideration, I'm also in the "have fun in the sun" camp.

I noticed the same. But I've sought moderate sun not deliberately but because I sense my body tells me to do it.

Our emotions can be wrong, but I guess it makes sense we'd evolve some reasonable senses about sun exposure.

Something like artificial and abundant sugar would be different since it did not exist.

There might be a lot of value in reasonable disobedience of authority and instead listening to your body.

Prehistoric humans were under a hell of a lot more environmental and physical stress than we are. Being healthier, not dying later, is going to be the objective of evolutionary pressures during that time.

> 7 does not seem valid (consider the case of sugar consumption)

How much refined sugar do you think people were eating in the environment of evolutionary adaptation?

(Although, I agree that causes of death change as life expectancy changes, and things that didn't matter before start to matter now that the low-hanging fruit has been picked)

The issue is that people nowadays may live in a place with a lot more UV than their ancestors adapted to -- consider an Irish family that moved to Arizona, for example. The same principle of "more available than evolution prepared you for" seems also to apply.

And vice versa - consider migration from Central America to Chicago or North Africa to Stockholm.

I don't think "refined" matters, except so far as once you refine sugar, you can add it to all kinds of foods, driving consumption up. That's exactly my point--eating some fruits or honey is good for your health when every calorie is valuable. Eating tons of sugar when it's cheap and added to everything is bad for your health. Just because eating some sugar was helpful in the past doesn't imply that our bodies have evolved to process arbitrarily large amounts of sugar with no ill effects whatsoever.

Another relevant point is that we evolved with a thicker ozone layer, and thus, considerably lower UV flux.

Is there any hard data on the actual UV levels when modern humans first evolved?