Your genes can effect how much you weight you gain. The success of a survival gene can be why plentiful food transforms into weight gain for some people more than others.
A survival mechanism that evolves to preserve a race during famine transforms into a dangerous liability once food is plentiful. That's the story science is telling about the "thrifty" gene, a gene whose discovery adds race to genetics as yet another explanation of obesity in humans.
|Where you don't want to gain weight|
|Scientists believe that race plays an important role in the incidence of obesity.|
|Studies on the Inuit of Canada and the Pimas of Arizona show that both groups have a high incidence of obesity that may be associated with genes.|
|Scientists speculate that the thrifty fat genes that protected certain racial groups during times of famine developed into a liability when food became plentiful.|
|The thrifty fat gene may cut across all racial groups. Some scientists believe that people whose parents or grandparents had little to eat are more prone to obesity than those who descend from generations of well fed.|
Take the Pimas of Gila River, Ariz. Members have an unusually high incidence of obesity and the highest recorded rate of type 2 diabetes in the world. A Gila River Pima man has an 80 percent chance of becoming diabetic before he's 55, according to a public health officer for the tribe.
Likewise, the Inuit of Canada have a gene variation (called GNB3) that correlates with a higher body mass index, the yardstick for measuring obesity, as well as larger waist and hip measurements, says a recent report in the journal Genome Research.
Such studies tell us that some ethnic groups evolved thrifty fat genes to survive famine. As long as they consumed a moderate amount of fruit, vegetables, fish and meat, body weight remained normal.
When the Inuit and Pimas abandoned their traditional lifestyles and adopted the eating habits of contemporary North America, their thrifty fat genes became a liability. With new eating habits, fat was stored, rather than metabolized, as would probably have been the case with other racial groups.
The thrifty gene may also be a factor in the higher incidence of obesity among Hispanics and blacks, according to some scientists. Additionally, studies of Caucasians show that those of wealthy ancestry are less susceptible to obesity than those descended from poverty.
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