London - Experts have called for a shift in the way our body mass index is calculated, after a study found that people classed as overweight live the longest.
The major study, spanning three decades, found that people with a BMI of 27 – who doctors would categorise as being overweight – now have the lowest risk of dying from any condition.
The BMI system compares someone’s weight with their height. Those with a score of 18.5 or under are considered “underweight”, 18.5 to 25 “normal”, above 25 “overweight” while over 30 is “obese”.
Researchers at Copenhagen University Hospital in Denmark showed that the healthiest measurement has increased by 3.3 points since the 1970s.
The team looked at three groups of people monitored at different times since the mid-70s – 13 704 tracked between 1976 and 1978, 9 482 tracked from 1991 to 1994, and 97 362 monitored from 2003 to 2013. They were all followed up until November 2014, or until they died or left the country. The results showed that the healthiest BMI value, associated with the lowest death rates, had increased from 23.7 in the first group to 27 in the last.
The authors, writing in the JAMA medical journal, wrote: “If this finding is confirmed in other studies, it would indicate a need to revise the WHO categories presently used to define overweight, which are based on data from before the 1990s.”
One reason for this change may be because improvements for heart disease treatments have benefited the overweight the most.
Another explanation could be that it is internal fat that is dangerous – so some thin people are in fact less healthy than those who are slightly chubby.
Daily Mail