Reasons we should be cautious of the new finding that being overweight reduces the risk of death

A recent article published in the Journal of the American Medical Association entitled “Association of All-Cause Mortality With Overweight and Obesity Using Standard Body Mass Index Categories concluded that “Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality.” In other words, based on body mass index, these authors found that being overweight was a good thing and that being obese is not a problem.

Well, here is the problem: the authors used body mass index (BMI). This is a ratio of one’s height and weight. It can be calculated by dividing your weight in kilograms by your height in meters-squared. A BMI of 18.5-24.9kg/m2 is considered to be normal where as a BMI of 25-29.9 is considered overweight and a BMI of 30-34.9 is considered grade 1 obese. The problem with this measure is that it does not take into account the distribution of fat. For example, let’s say I had a BMI of 28, but the majority of my fat was located in my thighs and arms. This may not be desirable, but it isn’t necessarily a health risk. It is when fat is located in the mid-section that we should be concerned. Specifically, fat located in the mid-section underneath the muscle i.e. visceral fat is of great concern. Waist circumference is therefore a better predictor of disease and mortality risk than BMI as it tells a more complete story. Let’s go back to my original example. If my BMI were 28 and I had a waist circumference of more than 88cm (102cm for males) then I would be at HIGH risk for death and diseases.

So, my quick take on this paper is that it should be ignored by the media and the general population. There is unequivocal data to show that being over-fat is a health risk. Granted, having a BMI that categorizes one as overweight or obese doesn’t necessarily mean the person is over-fat. It is because of these limitations that the Edmonton Obesity Staging System was created. Please read my previous post on this comprehensive approach here: http://sdogra.com/2012/06/18/healthy-obese/ and please stay committed to your Healthy Active Lifestyle Forever!

 

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