New research suggests that body shape is more important than body mass index (BMI) in predicting mortality.
We’ve known for some time that if you’re overweight, an “apple shape,” meaning extra fat around the middle, is worse for your health than a “pear shape,” meaning the extra weight is on your hips and thighs.
The BMI gives an approximation of how fat you are. The problem is that if you have a lot of muscle, the extra muscle will increase your BMI, but it will also improve your health. So in that case the BMI isn’t a reliable indicator of health risk.
In the past, we haven’t had a simple measure for body shape. But now researchers have come up with A Body Shape Index (ABSI) that is supposed to quantify body shape. It takes waist circumference as well as height and BMI into account. If you’re into statistics and math, this paper will show you how the ABSI is derived.
For the rest of us, an ABSI calculator has been developed. It’s fun to play with.
I first put in my real data and got the results. Then I wondered what would happen if I lost 20 pounds, so I put in that hypothetical weight, expecting lower risk. But instead my risk doubled! Thinking about it, I realized that if my waist circumferance stayed the same but the rest of my body got thinner, it would mean that most of my weight was in my stomach, a real apple shape.
What if I gained 30 pounds? Then my risk would go down. This is assuming again that my waist stayed the same, which would be unlikely. But if I could gain 30 pounds of muscle with no increased abdominal fat, I’d be healthier.
What if I were 18 years old? Then my risk from BMI alone would go down, but my risk from ABSI would go up. Why? I suspect they assume that a younger person would have less fat and more muscle, which would decrease risk measured by BMI. But a younger person would be more likely to have a flat stomach, so having my shape would indicate that something was wrong.
The calculator produces even more parameters like z-scores, which compare your results with the mean, but most of us wouldn’t find those very useful.
It might be useful to plug your information into the calculator and see what changes would make the risk go down the most. For example, you could keep inputting lower and lower waist circumferences until your risk was less than one. That would be your goal.
In my case, growing a foot would do wonders for my BMI, but if I didn’t gain weight as well, my risk would triple. I guess I’ll have to abandon my plans for getting a lot taller.
Published On: March 01, 2014