| | | | | | particularly Asians, eating food rich in |
| | | | | saturated fats will generally increase the |
| | | | | level of “bad” cholesterol and decrease |
| | | | | the “good” cholesterol. “When Asians |
| | | | | move from their traditional environment |
| | | | | to the West” - or when they start eating |
| | | | | at their local McDonald’s in Tokyo or |
| | | | | Beijing - “they immediately get into |
| | | | | trouble with obesity and heart disease - |
| | | | | more than Caucasians,” says Jose |
| | By Fred Guterl with Anne Underwood | | | | Ordovas, director of the Nutrition and |
| | | | | | Genomics Laboratory at Tufts |
1 | | Of nature’s many weather | | | | University. By the same token, Northern |
| | conditions, winter at the Arctic Circle | | | | Europeans and Celts, and some |
| | would have to be one of the harshest. | | | | Mediterranean populations, tend to have |
| | It’s hard to imagine that humans would | | | | the same cholesterol levels no matter |
| | have survived generations of frigid | | | | what they eat - the work of a gene |
| | climate without some adaptation giving | | | | inherited from Viking ancestors. |
| | them a way to cope. Scientists have in | | 5 | | A person’s vulnerability to the |
| | fact put forward a theory about a “thrifty | | | | diseases associated with obesity |
| | genotype” that some humans acquired | | | | depends not just on diet but on his level |
| | 30,000 or so years ago during their | | | | of activity as well. And there’s some |
| | migration from Asia, across a land | | | | evidence that activity is a product of |
| | bridge at what’s now the Bering Strait, to | | | | biology as well as culture. A paper |
| | North America. These genes may have | | | | published by Dr. James Levine, a |
| | given cold warriors an ability to store fat | | | | nutritionist and endocrinologist at the |
| | and metabolize it sparingly, a handy trait | | | | Mayo Clinic in Rochester, Minnesota, |
| | for the dark, cold months when food is | | | | reports that a genetic predisposition to |
2 | | Now that the land bridge is long | | | | obesity may turn on how much a person |
| | gone, the descendants of these first | | | | fidgets. People who fidget turned out to |
| | North Americans are stuck with genes | | | | expend 350 calories a day more on |
| | optimized for life in the Ice Age. The | | | | average than those who don’t - the |
| | same traits that allowed their ancestors | | | | equivalent of a weight gain of 30 or 40 |
| | to thrive in the Arctic wilderness may be | | | | pounds in a year - merely by getting up |
| | making them uniquely vulnerable to the | | | | and moving around more. Studies |
| | high-fat, high-cholesterol, sedentary | | | | suggest a neurochemical basis for the |
| | American lifestyle. The problem with | | | |
natural tendency to fidget. 29 , rats |
| | evolution is that it can't keep pace with | | | | injected with the neuropeptide orexin |
| | the modern world. | | | | began to “run around their cages like |
3 | | Asians are thought to possess many | | | | crazy,” says Levine. But scientists are |
| | of the “thrifty-genome traits”, which may | | | | only beginning to get a handle on the |
| | explain why the number of obese | | | | problem. There’s a possibility that fat in |
| | Chinese doubled between 1992 and | | | | the body slows down the metabolism |
| | 2002 to 60 million, according to China’s | | | | over the long term. What’s certain is that |
| | Health Ministry. Some Mediterraneans | | | | thrifty genes work in more complex ways |
| | and Africans may not have acquired the | | | | than scientists appreciate at present. |
| | thrifty genes of Arctic peoples, but their | | | | “There’s a profound interplay going on |
| | hunting-and-gathering ancestors didn’t | | | | between the amount of energy people |
| | leave them a whole lot better equipped. | | | | take in and their level of activity,” he |
| | Half of Brazil is now overweight, and | | | | says. |
| | one in eight is obese. In France and | | 6 | | The question scientists would |
| | Italy, about one in three is overweight, | | | | ultimately like to answer is how to |
| | and the proportion is rising. All told, | | | | compensate for the obsolete genes |
| | about 1.2 billion people in the world are | | | | we’ve inherited from our primitive |
| | fat, and another 350 million are obese. | | | | ancestors. Identifying the hundreds of |
| | Obesity-related illnesses, such as heart | | | | genes involved - let alone figuring out |
| | disease and diabetes, are rising. | | | |
how to 32 their ill effects - won’t be |
4 | | Scientists are beginning to | | | | easy. Undoing thousands of years of |
| | appreciate the variations in how different | | | | evolution never is. |
| | people respond to diet. For most people, | |
Newsweek |