New Delhi, Nov 25: Millions of Indians certified as fit today may need to lose weight to retain that tag of health under new definitions for obesity tailored for the Indian population released by experts today.

A group of medical experts has finalised new cut-off values for waistlines and measures of weight to classify Indians as overweight or obese that are more stringent than the international values used until now.

International guidelines classify a person with a body mass index -- the ratio of the weight in kilograms to the height in metres squared -- between 25 and 30 as overweight, and greater than 30 as obese. Under the new values for Indians, any adolescent or adult with a body mass index between 23 and 25 would be overweight, and a value higher than 25 would make a person obese.

“This revision has been long overdue,” said Anoop Misra, head of diabetes and metabolic diseases division at the Fortis Hospital, New Delhi. “The new values will have tremendous public health implications,” he said.

The expert group has also revised healthy waistlines values for Indians -- 90 cm for instead of 102 cm for men, and 80 cm instead of 88 cm for women. “Abdominal fat is the most dangerous fat to have,” Misra said. “India has a huge burden of this problem.”

Surveys in some Indian cities have indicated that one in three adults is overweight, or obese or has abdominal fat. The International Diabetes Federation estimates that India has about 41 million people with diabetes.

Doctors are hoping the new cut-offs would prompt people to reassess their fitness and take steps to reduce obesity --a major risk factor for diabetes, cardiovascular disease, high blood pressure, and stroke.

“The revision could benefit an additional 10 to 12 per cent of the population,” said Misra, who was co-convener of a meeting of about 150 experts drawn from institutions across India who approved the guidelines. The National Institute of Nutrition, the All India Institute of Medical Sciences, the Diabetes Foundation of India, and Association of Physicians of India were represented at the meeting.

Several studies have shown that sickness and death from obesity-related illnesses is lowest among Caucasians with body mass index values between 18 and 25. But it is lowest among Indians with body mass index between 18 and 23.

Citing medical studies, researchers have over the past five years often suggested revised obesity cut-offs because Indians they have a different body composition and a higher risk of diabetes and heart disease than Caucasians. After a series of consultations, a panel set up by the World Health Organisation two years ago had suggested that countries should pencil their own cut-off values for obesity.

Under the new obesity guidelines, Indians would need to consider drug treatment when the body mass index touches 25, instead of the international practice of considering therapy only at a body mass index of 27.

“The first action should be lifestyle modification -- exercise and a regulated diet,” said Brij Makkar, an obesity specialist in Delhi and member of the group. “But people who don’t respond to lifestyle changes alone need to consider drug therapy.” Anti-obesity drugs work by getting the body to suppress fat production and excrete more fat than usual, but need to be taken under supervision.

The expert group has recommended that overweight or obese Indians should aim for 60 minutes of physical activity or exercise a day. “This doesn’t have to all at once, but could be spread into blocks of 20 minutes each,” Makkar said.

For the extremely obese, the group has revised rules for bariatric surgery that can help people eat less and lose weight. Indians with a body mass index of 32.5 would be candidates for surgery which is offered only at index values of 35 or higher abroad.

“We had been blindly using Western guidelines,” said Pradeep Choubey, head of bariatric surgery at the Sir Ganga Ram Hospital, New Delhi, and convener of the expert group which plans to circulate the guidelines to doctors across the country.