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Measure of obesity redefined
RESEARCHERS in Europe and the US define the normal limits of body mass index (BMI) as a measure of obesity. The International Task Force on Obesity and the World Health Organization take these limits as universally applicable. But researchers in India have challenged this standard as it is based on the Caucasian body. They ask, “How can this standard be applicable to Indians and other Asians whose bodies are different?”
BMI, expressed in kilogram per metre square (kg/m2), is the ratio of a person’s weight and height that takes into consideration the total composition of fat, muscle, bone and tissues in the human body. This led to the first-ever definition of obesity: those with BMI 25-29.9 kg/m2 were classified as overweight and those with BMI above 30 kg/m2 were classified obese.
Anoop Misra, a professor at the department of internal medicine, All India Institute of Medical Sciences, New Delhi, discussed this at a South Asian media moot organized by the Centre of Science and Environment in New Delhi last month.
Speaking to journalists from India, Pakistan, Bangladesh, Sri Lanka and Nepal on the second day of the event, Prof. Misra said obesity is considered one of the strongest risk factors for diabetes. He pointed out that while the number of diabetics among his patients recorded a rise, most of the patients were not obese. The anomaly was intriguing.
“Assuming that at a BMI of 25-26 kg/m2, 10 per cent of the Caucasians have diabetes, then Asians achieve that 10 per cent at a BMI of 22 kg/m2,” said Prof Misra in his presentation. “It means that Asians can be classified as overweight or obese at a BMI lower than that for a Caucasians for the simple reason that the two races are genetically different.”
He said diseases caused by a high body fat content such as lipid disorders and cardiovascular diseases are noticed in the Asian population at a lower BMI than that for Caucasians.
“It is because South Asians have less muscle content and more fat content. The cause may be genetic but the problem is compounded when the people of South Asia turn to fast food that has become the lifestyle in the West. Fast food or the ‘junk food’ is laden with saturated fats. It contains lots of carbohydrates and less fibre. Our urban population, specially the younger generation, takes up the habit of eating junk food as a more ‘westernized’ lifestyle, but it makes them gain fat really fast,” Prof Misra said.
He further pointed out that another factor that contributes to lower muscle mass among Asians, especially South Asians, is under-nutrition among pregnant mothers because of which the babies born have a lower muscle content.
“When the body is starved of proteins, it may begin to store up fat in place of muscles,” he speculated, adding, “but that needs to be researched.”
Prof. Anoop Misra said WHO has to redefine the BMI for Asians.
The writer
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