[nostrademons]

It correlates with socioeconomic status. During the middle ages, fat women were considered attractive because it indicated that you had ample food available, a sign of wealth. Now thin women are desirable because it shows you have time to exercise, money for a gym membership, and don't eat at McDonalds.

Same goes for many other physical attributes. In much of Africa and Asia, whiter skin is attractive because white foreigners have all the wealth and power. In the U.S, tanned skin is attractive because it shows that you spend all day on the beach, which means you're wealthy enough to live near the ocean and leisured enough to spend time in the sun.

Humans seem biologically programmed to favor mates that are wealthy and powerful. However, the specifics of "wealthy and powerful" aren't hardwired in, so we take our cues from physical characteristics that appear correlated with wealth and power. When I was a kid, the girls would make fun of all the geeks. Now that geeks tend to be millionaires, they've reversed their tune.

[ajju]

>In much of Africa and Asia, whiter skin is attractive because white >foreigners have all the wealth and power.

This is not true, at least not the way you think. Attraction to (bias for) fair skin is a very very old tradition in India. If you look at Ramayana - one of the two Hindu religious epics which is at least thousands of years old, Sita, the main female character is described as fair many many times.

It has been argued that the fascination with fair skin came about because of the Indo-Aryan migration (http://en.wikipedia.org/wiki/Indo-Aryan_migration) though some people have argued that Aryans were indigenous to India as far back as the Harappan civilization. (http://en.wikipedia.org/wiki/Indigenous_Aryans)

That many of the ruler classes (The Chitpavan Brahmins in Maharashtra http://en.wikipedia.org/wiki/Chitpavan and the Moghul Nawabs) had fair skin may also have contributed.

[gommm]

In china and in japan, I don't think it's related to the wealth of white foreigners but more to the fact that peasant who work all day in the field will be more tanned...

Hence, not being tanned was the same as being fat. It showed that one had wealth and didn't need to work hard to get it.

Another possible explanation (at least in japan) is a question of geography. The center of power in japan has usually been around Tokyo or Kyoto and people there tend to be more lightly skinned as people from the south.

[byrneseyeview]

That's true, but I was noting that these 'wealth' and 'power' physical attributes can be genetic.