Slate: Did fat genes evolve for cold weather?

[Jane]

Fat, diabetic, and heart-disease genes may have evolved to survive the cold.

Researchers looked for correlations between climate (represented by different populations around the world) and genes related to energy metabolism. Result: They found them. Examples: appetite, sodium retention, blood pressure, blood sugar, cholesterol, metabolic rate, BMI, and abdominal girth.

Theory:
1) "Climate has been an important selective pressure acting on candidate genes for common metabolic disorders."
2) Specifically, our ancestors "had to develop genetic variants that made them more efficient in terms of energy metabolism and that made them more able to cope with cold climates by increasing their … ability to generate and maintain heat."
3) Today, "We eat a lot more, we don't exercise nearly as much as our ancestors used to do, and these adaptations that made us cope well to a cold climate now make us prone to a number of metabolic disorders."

Human Nature's takeaway: Today's genetic superiority (thin and non-diabetic) is yesterday's genetic inferiority.

http://www.slate.com/id/2184675/

[stefanie]

Being rounder means you have more mass per surface area, and thus tend to retain heat better.

What I wonder, though - was sub-equatorial Africa colder in the ice ages than it is now? Because obviously not just Europeans profit from "thrifty genes."

I find this a fascinating issue. What we call "metabolic disorders" today might not have been so in the past (probably right up to the invention of agriculture.) For one thing, there were probably very few naturally occurring sweets, outside of seasonal fruits and honey (which can be quite hard to harvest without full beekeeper regalia!) If you wanted carbohydrates pre-agriculture, you had to work hard for them (finding them, digging them, carrying them, cooking them.) Fat wasn't a demonized food - you were lucky to get it. The native Americans knew about "rabbit starvation" - if you're eating pure lean protein and nothing else in cold enough weather, for long enough, you'll starve.

The point is that these thrifty genes are *designed* to make us get fat, especially when we find the carbohydrates that were so relatively scarce in the past 100,000 years.

It also makes sense that there would be a *variety* of genes in the population. That's why you have people who can eat very little, and still keep on going. If everyone sucumbed to starvation at the same rate, the population would die out. Those populations with more genetic variability would have more 'aces' in their hand, so to speak.

[Jane]

Originally Posted by stefanie

Being rounder means you have more mass per surface area, and thus tend to retain heat better.

What I wonder, though - was sub-equatorial Africa colder in the ice ages than it is now? Because obviously not just Europeans profit from "thrifty genes."

I find this a fascinating issue. What we call "metabolic disorders" today might not have been so in the past (probably right up to the invention of agriculture.) For one thing, there were probably very few naturally occurring sweets, outside of seasonal fruits and honey (which can be quite hard to harvest without full beekeeper regalia!) If you wanted carbohydrates pre-agriculture, you had to work hard for them (finding them, digging them, carrying them, cooking them.) Fat wasn't a demonized food - you were lucky to get it. The native Americans knew about "rabbit starvation" - if you're eating pure lean protein and nothing else in cold enough weather, for long enough, you'll starve.

The point is that these thrifty genes are *designed* to make us get fat, especially when we find the carbohydrates that were so relatively scarce in the past 100,000 years.

It also makes sense that there would be a *variety* of genes in the population. That's why you have people who can eat very little, and still keep on going. If everyone sucumbed to starvation at the same rate, the population would die out. Those populations with more genetic variability would have more 'aces' in their hand, so to speak.

I've always said that genetically, I was made to live through a potato famine.

[stefanie]

Originally Posted by Jane

I've always said that genetically, I was made to live through a potato famine.

That reminds me of something from the Frank McCourt book, Angela's Ashes. Frank grew up in a poor Irish family (in Limerick City), and his mother Angela was very thin. When he finally emigrated to NY, and brought Angela with him, he mentions almost parenthetically that she put on quite a lot of weight. Some might have been her age, but some simply might have been her "thrifty" body finally able to reverse the years of near starvation.

[D_A_Bunny]

Hallelujah! I say this all the time. That fat people were meant to be the "survivors of the fittest". Meaning exactly what you have posted. That we would survive a famine. Alot of times people envision "surviving" as being in a jungle, running from a lion or tiger. Reality is, that surviving would mean living longer without as much food.
They have also proven in the past that women generally begin putting weight on in their lower abdomens. This is to protect the womb.
So, maybe this can lead to a real discussion in the world that shows that our bodies are biologically correct and that current society has made us "excessively" fat. Meaning - our bodies are doing what they were genetically programmed to do but in this day and age we no longer actually need to be this way to survive. We have access to more food and less requirement to physically work for it.
So, just like the size of my nose or the color of my hair, I was born to be Fat.
I knew I wasn't crazy! (well, maybe a little)

PS - I also posted in another thread that I feel that this is also why there are FAs and FFAs. They are here to help and keep the fat fed so that we would all survive. Gotta work together you know.

[Just_Jen]

wuhaha now i know that when im telling my thin friends moaning about being cold that im fine because i have insulation; its so true

it'll be just us and the cockroaches baaaybeh!