Being overweight as defined by your BMI is not unhealthy says Dr Malcolm Kendrick, a GP and researcher, who has written a book which debunks the medical advice on what is a healthy weight. ‘Doctoring Data - How to sort out medical advice from medical nonsense’
He contends that most medical research lumps people together into too few groups which skews the results. Obesity researchers clump people together into 4 main groups; underweight, normal, overweight and obese.
They do this by assigning a BMI to each group 18-21 is underweight, 21-25 is normal weight, 25-30 is overweight, 30+ is obese.
But what this means is that those with a BMI of 31 are clumped together with those of a BMI of 50 and above. So we have not been given evidence of the health risks of those with a BMI which falls between these two.
By assigning just these four weight groups medical experts are giving out the message that anything other than a normal BMI of 21-25 is less than healthy. However Dr Kendrick’s own research into the studies that produced these weight groups unearths papers in the Journal of the American Medical Association that “overweight was not associated with excess mortality”. Digging further he came across the paper’s conclusion that those who were in this category actually lived the longest.
Dr Kendrick has found that many so-called medical facts are simply not true; he cites a former editor of the British Medical Journal, Richard Smith, who reveals that the level for safe drinking was simply “plucked from the air”.
As a team member of the Royal College of Physicians their remit was to produce guidelines on safe alcohol use. However the lead epidemiologist admitted that there was no data about safe limits available and so the committee came up with an “intelligent guess”. In time this guess becomes established fact and is promoted by the government as safe drinking limits.
The advice on what is considered a normal weight is similarly skewed by research findings that have been selectively chosen to support the prevailing views.
A meta analysis (a paper that brings together a large number of trials and studies) conducted in 2009 on above normal weight and obesity came to the conclusion that “The prevailing notion that this increases morbidity and mortality, as compared with normal weight, is in need of further specification”.
The accepted stance of the medical fraternity was so entrenched that the report was afraid to state clearly that having a BMI in the range 25-30 (overweight) was not only healthy but actually increased your life expectancy compared to those with a BMI of 21-25 (normal).