Folks here probably know about the BMI– and possibly are familiar with my, ahem, “issues” with it as a tool of diagnosis; anything that bases treatment choices on the assumption that bones, fat and muscle all weigh the same, and people are identically proportioned, is going to get me angry. Add in it being changed in 2000 by over 2kg/m2 (so that “overweight” is 25kg/m2; BMI is weight in kg divided by height in meters, squared) to make it easier to calculate and remove the differences between men and women and…well, I’m getting distracted.
Anyways, the BMI is the basis for the “obesity epidemic” we’ve all heard about, and there are calls for action on the following theory that this generation will die earlier than their parents.
Shockingly, some scientist actually decided to do research to see if being over-weight or obese by this BMI standard resulted in dying earlier. It’s clear that if you’re heavy enough, you do die earlier, but that’s diagnosis by examining actual people, not by applying a broad standardized calculation.
There’s a problem: they didn’t confirm what “everyone knows.”
The news will seem heaven sent to those contemplating a new year diet, and contradicts the received wisdom that being fat reduces life expectancy. It is the second time that research studies led by Katherine Flegal, a distinguished epidemiologist from the National Centre for Health Statistics at the Centres for Disease Control and Prevention in Maryland, US, have studied the link between obesity and mortality.
In 2007 the same group caused consternation among public health professionals when they published the results of a similar analysis that also showed being fat does not shorten life. Walter Willett, professor of nutrition at Harvard School of Public Health, dismissed the finding as “rubbish”.
Dr Flegal told The Independent she had decided to conduct a second, larger, study on the same theme to counter the sceptics. She and her team examined results from 100 studies from around the world, involving three million people and 270,000 deaths.