New Canadian research suggests putting on weight could present potentially more serious problems for people of South Asian origin compared with other populations.
The findings may help explain why South Asians, Canada's largest visible minority population, are more likely to develop cardiovascular disease than white populations, even if they have similar body mass indexes.
Researchers discovered that South Asian people don't have as much room under the skin as white people and therefore store more fat inside the abdomen and in organs, such as the liver or even the heart, which can create metabolic problems and increase the chances of developing Type 2 diabetes, stroke or cardiovascular disease.
"This means, that for the same level of BMI, South Asians are much more likely to develop diabetes or heart disease," Arya Sharma, director of the Canadian Obesity Network, chair of obesity research and management at the University of Alberta and study co-author said in an e-mail.
But the study, published Thursday in the journal Public Library of Science ONE, also underscores how much remains unknown about why people who originate from the Indian subcontinent seem to be at greater risk for a host of health problems and the urgent need for more research.
"It's the major health concern of South Asians globally as well as in Canada," said Sonia Anand, lead author of the study and professor of medicine and epidemiology at McMaster University in Hamilton.
Burning questions centre on what role genes and the environment play in contributing to the increased health risks.
"It's still kind of a big open question," Dr. Anand said.
In the study, researchers compared 108 healthy South Asians and Caucasians around the same age, grouped according to similar weight. They found South Asian people are more likely to store fat in the abdomen and organs, which experts say is dangerous because it can interfere with their proper function and lead to serious health problems.
Concerns over internal fat surrounding organs is the main reason why many doctors now warn patients that carrying extra belly fat could be a warning sign of major health issues.
Although it's not well understood why South Asians face certain higher health risks, experts believe some combination of environmental and genetic factors may be at play. For instance, South Asian people may have certain genetic characteristics that make them more vulnerable to the effects of weight gain, while decreases in physical activity are leading to higher rates of overweight and obesity.
Some suggest the culprit may be the Western diet, heavy on fat, simple carbohydrates and processed foods, which South Asian immigrants may come to rely on.
But Dr. Anand said that theory is likely flawed because research based in South Asian countries comparing urban and rural areas found rapidly increasing rates of Type 2 diabetes, cardiovascular disease and other health problems among city-dwellers.
She believes rapid urbanization, which may lead to reduced physical activity and fewer calories burned, could help explain the phenomenon.
As the research continues, experts say there is an urgent need to launch prevention and education programs targeted at South Asian populations. Some say people of South Asian origin should be screened for Type 2 diabetes even if they don't appear to be seriously overweight. In addition, "obesity prevention and treatments have to be considered at lower body weights than in Caucasians," Dr. Sharma wrote.
Aditya Jha hopes he can benefit from listening to his doctor's advice about the importance of obesity prevention. Mr. Jha, a patient of Dr. Anand's, said she told him he was in the beginning stages of Type 2 diabetes and should take control of his health through diet and exercise.
Now, Mr. Jha, a well-known Indian-born entrepreneur and philanthropist based in Toronto, says he is now much more careful about his eating habits and exercises several times a week, including a boxing fitness program.
The problem is that too few people of South Asian origin recognize the risks they face, he said, something that has to change in order to help protect the population.
"There's not realization, deeper realization, that this is a problem," Mr. Jha said.