Famines cause ability to store fat more easily: abdominal fat more dangerous for South Asians

According to a theory, Asia underwent more famines than Europe - causing its people to evolve the ability to store fat more easily. Scott Lear, a kinesiology professor at Simon Fraser University who led the study, said the ethnic gap is so profound that it may be necessary to redefine what obesity means for Asians.
A new study of Canadian scientists says that abdominal fat is more dangerous for people of Chinese and South Asian descent, as compared to Caucasians.
Researchers measured the body fat of more than 800 volunteers in Greater Vancouver of various ethnic backgrounds, says a report published in Vancouver Sun.
What they found is that, for the same amount of total body fat, Chinese and South Asian people had a far greater concentration of fat in their inner abdomen - where it poses the greatest risk for diabetes and heart disease.
For example, the study found that a moderately overweight Chinese person has, on average, 36 percent more inner-abdominal fat than a Caucasian person of the same size. And a South Asian of average weight has 23 percent more inner-abdominal fat than someone Caucasian. Aboriginals showed no difference from Caucasians.
At the moment, regardless of ethnic background, you are considered at risk of health problems if you have a waist circumference larger than 102 centimetres (40 inches) for men or 88 centimeters (35 inches) for women.
Given the added health risks weight seems to pose for Asians, said Lear, it may make sense to create new, ethnic-specific weight standards for them - such as 90 centimetres (35 inches) for men and 80 centimetres (32 inches) for women.
Lear said the definition of overweight under the Body Mass Index, a calculation based on height and weight, may also need to change for Asians, dropping from 25 to 23. "We're in the process of coming up with some guidance for what the [new ] targets should be," he said.
Lear doesn't know why Asians accumulate fat differently. But the ethnic gap persists even after controlling for things like diet, height and level of exercise, suggesting it has something to do with genetics.
In recent years, scientists have discovered that overall weight is far less important for good health than where that weight is distributed - with abdominal, or belly, fat most closely linked with heart disease and diabetes.
And while most people focus on subcutaneous fat, the belly fat they can pinch under their skin, it is actually the abdominal fat deep within the body that is the most dangerous. It is this fat that Lear's team studied by taking CT scans of people's bellies.
Exactly why inner-abdominal fat is so unhealthy is not known, though it may be that it puts greater stress on the liver. Rema Sanghera, a dietitian at BC Women's Hospital, works with pregnant women from various ethnic backgrounds to reduce their risk of diabetes.
"Our hope is that, since mom is the chief cook in the family, that changes she makes will have a trickle-down effect for other family members as well," she said.
Sanghera said the incidence of diabetes among South Asians is several times that of the general population. She said she hopes Lear's study results in new guidelines for health workers like herself - so they can do a better job of identifying unhealthy weight in Asians. Lear's study is published in the current edition of the American Journal of Clinical Nutrition.