Monday, September 22, 2008

Science Vocab: Thrifty Genes


The other day, I hinted about my struggle with weight. Carrying extra weight is not healthy, but for some people shedding pounds is a challenge. It is for me. I blame my thrifty genes for some of my struggles.

The Thrifty Gene Hypothesis was first presented in the 1960's. It basically says that the among some ethnicities, their genes for metabolism work differently.
People from ethnic groups like Africans, Native Americans, and Polynesians evolved in areas where there were routine food shortages, due to extended dry seasons or cyclic famines.
Those individuals who carried a little extra fat -- in the hips, stomach, thighs or where ever --survived hungry times better. They carried more fat because of how their bodies metabolized carbs. Instead of burning it all off, their metabolisms were frugal or thrifty, burning less energy and storing more of it as fat.
I personally think the term Thrifty Genes isn't the best description. I prefer Famine-Resistance Body Type.

Fast-forward to the pro-industrial age.
We definitely have a more sedentary lifestyle than our ancestors. We put less energy into farming, chasing down game, gathering food, and preparing and cooking food.
Also, food is more regularly available - in the Industrialized world, fewer chances of famine and food shortages.
We also have a lot of processed, high carb, high sugar foods - more caloric-bang for the portion size. Those of us who have ancestors who successfully lived in these harsher conditions, but inherited their "good famine-resistant genes" are now at a disadvantage. Our genes and physiology are pre-programed - save more, burn less and there is little we can about it - other than eat differently and exercise more.

This hypothesis is presented as plausible, though not definitive, explanation for why African-Americans, Native-Americans, and Polynesian peoples have a higher propensity for weight issues and health problems like diabetes and heart diseases.

3 comments:

Torrance Stephens - All-Mi-T said...

good one, need to chk out them folk in the neterlands

TJ said...

I was about to say, what are thrifty genes? They make you shop at Walmart? What?

I've always thought something along those lines (genetic adjustment to famine and much harder and longer work days) was a major reason for the obesity epidemic among people of color.

Treva said...

I appreciate the information you provided. I especially like the fact that you expressed that this theory was definitive. I am writing a paper on obesity in america, and this information gave me a better understanding of my own situation. As you said, even if we are "pre-destined" to be overweight, there is not much we can do about it except exercise and eat right. That is the ONLY thing that works for me. The minute I stop exercising, the weight comes right back. Thanks Urban Scientist for your insight.