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Unable to shed fat? Blame it on your ancestors
Scientists now postulate that a "thrifty gene" acquired by humans 30,000 yrs ago during migration from Asia to North America, is responsible for deposition of fat.
Unable to shed fat? Don't blame yourself but a "thrifty gene" acquired by your ancestors 30,000 years ago.
Scientists are now postulating that the "thrifty gene" was acquired during migration from Asia across the land bridge at what is now the Bering Strait to North America.
These genes might have given warriors an ability to store fat and metabolise it sparingly, a trait needed to survive the dark, cold months when food is scarce, Newsweek reports in its upcoming issue.
Now that the land bridge has gone, the descendants of these first North Americans are stuck with the gene optimised for life in age, the same gene that allowed their ancestors to thrive in Artic weather, maybe making them uniquely vulnerable to the high-fat, high-cholesterol and sedentary American lifestyle, the report says.
Members of the Pima tribe of Arizona, for instance, suffer from one of the world's highest rates of diabetes.
Fifty per cent of adults over the age of 35 and 95 per cent of those suffering from diabetes are overweight, it says adding that the problem with evolution is that it cannot keep pace with the modern world.
Asians are thought to possess many of the Pimas' thrifty-genome traits, which may explain why the number of obese Chinese doubled between 1992 and 2002 to 60 million, the Newsweek reports quoting figures from China's Health Ministry.
Some Mediterraneans and Africans may not have acquired the thrifty genes of Arctic peoples, but their hunting-and-gathering ancestors did not leave them a whole lot better equipped, the report says.
Half of Brazil is now overweight, and one in eight is obese. In France and Italy, about one in three persons is overweight and the proportion is rising, the report says.
Altogether, about 1.2 billion people in the world are fat, another 350 million are obese and illnesses such as heart disease and diabetes are rising, it says.
Scientists are beginning to appreciate the variations in how different people respond to diet.
For most people, 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," Jose Ordovas, director of the Nutrition and Genomics Laboratory at Tufts University, was quoted as saying.
By the same token, Northern Europeans and Celts, and some Mediterranean populations, tend to have the same cholesterol levels no matter what they eat — the result of a gene inherited from Viking ancestors.
A person's vulnerability to the diseases associated with obesity depends not just on diet but on his level of activity as well, scientists say. And there is some evidence that activity is a product of biology as well as culture.
