The issue is not all about being a big boy only. You can be big, fat and healthy, if you practice sports and an obese (inside) skinny couch potato. The question is not just "how much" but also "where".

A recent research has shown that different ethnic groups tend to store fat exactly where it does induce more harm. People of Chinese and South Asian (Indian) ancestry tend to store more inner abdominal fat than people of European ancestry, rendering them more vulnerable to weight-related diseases, like metabolic syndrome, heart disease, high blood pressure and diabetes.

Currently, in US, 1.2 % of the population has Chinese ancestry and 0.8 % are from India, while in Canada, the numbers are higher: 3.5 % and 3 %.

"The results show that current methods for measuring body fat may not be accurate for people who are not of European descent because the targets generally used for waist circumference or body mass index (BMI) are based on studies whose participants were predominately of Caucasian European origin," said lead researcher Dr. Scott Lear, an assistant professor at the School of Kinesiology at Simon Fraser University in Burnaby, British Columbia.

This could result tricky in early detection of weight-related issues when dealing with people in certain ethnic groups, even they can have more problems when having the same size as Europeans. The research was made on 800 healthy Chinese, South Asian, Aboriginal and European participants, each group in similar numbers.

"The participants' amounts of abdominal fat were compared for the same amount of total body fat, because in a random sample, the Chinese and South Asians would tend to be smaller than the Europeans and would have less overall body fat even at the same body mass index (BMI) or body fat percentage," said Lear.

Inner abdominal (visceral) fat is not what you grab when pinching on your abdomen. This fat is located behind the abdominal muscles, wrapping the bowels and it is more strongly linked to health issues. Skinny people can have plenty of it, while robust, sportive people can have little.

The study revealed that Aboriginals didn't present any difference in their body fat distribution compared to Europeans, but the Chinese and Indian subjects had a higher percentage of visceral fat.

Even when the researchers took into account other factors, like diet, physical activity, smoking, education and income, the differences persisted.

"What that lends us to believe is that there's some physiological or genetic rule that is deciding that a higher proportion of fat goes into the abdominal area in Asians than it does in Europeans," explained Lear.

"In order to get a better idea of the risks a person faces from visceral fat, waist circumference should be used in place of BMI measurement".

BMI is determined now based on weight and height, that's why a muscled person can appear overweight based on BMI, even if he/she has a low body fat level. Waist size usually increases due to visceral fat and would be a better tool for measuring BMI.

"If we wait until Asians reach the size of Europeans, they're going to be at a higher risk than the Europeans and may already present with diabetes or high cholesterol," warned Lear.

The researchers are looking now for genes linked to body fat distribution across different races. The study's subjects will be monitored 5 years, to assess how weight shifts affect their health.

"There is no reason to believe their results wouldn't apply to Chinese and South Asians living around the world, including those living in China or South Asia. Chinese populations in China and South Asians in South Asia currently have lower obesity rates than seen in North America, but those rates are rapidly increasing, and at a faster rate. If it reaches the same level as Canada, the United States and European countries, the Asian countries are going to experience a far greater burden of heart disease and diabetes than we ever saw." said Lear.