Saturday, July 16, 2011

Is my "BMI" reliable or should I get my "Percent Body Fat" checked?


Let me start by saying that at 5'9" and 185 lbs, I am "Overweight" bordering on "Obese" according to the BMI (Body Mass Index) Index and yet I am around 13% body fat which is "athletic" or "Fit" on the American Council on Exercise Percent Bodyfat Index. Really? Why?

Well, because BMI is dependent only on weight and height, it makes simplistic assumptions about the distribution of muscle and bone mass, and overestimates fat on those with more lean body mass like myself, while underestimating fat on those with less lean body mass like the elderly. And what's crazy is that as we all lose a little height through aging without any corresponding increase in weight, our BMI increases magically! In my opinion the error in BMI is significant and pervasive enough that it is not useful as a health evaluation tool.

Your true body fat level can be determined by such techniques as skinfold measurements or underwater weighing to name a few. The term "Body Composition” is used to describe the different components that collectively make up your body weight. Lean tissues, such as muscle, bone, and organs are metabolically active, while adipose (fat) tissue is not.

Body fat percent between 6%-17% for men and 14%-24% for women is considered generally healthy and there is a dramatic correlation with illness and disease for men over 25% and women over 32%.

In light of the above, I would highly recommend having a handle on your body composition. A slight daily deficit between your caloric intake and output is the most effective way to accomplish a leaner healthier body. A quick body composition analysis can estimate the correct caloric intake based on your current lean body mass so appropriate adjustments to your exercise routine and diet can be made.

At our Clinic we use Skinfold Measurements to determine body composition and DietMaster Pro to develop precise nutrition plans, and the whole process takes less than an hour.