March 15, 2014

Week 8: Body Mass Index and Me

I set my initial weight loss goal of 180 lbs because it seemed to me that 100 lbs was a nice round number.  I also recall back in 1979 thinking to myself for the first (and last) time that I was starting to look fat, at the time I weighed 183 lbs.  As it goes 183 lbs is just within the normal weight range for my height as outlined by the Body Mass Index commonly referred to as the BMI.

BMI is a guideline on body fatness based on height and weight.  It is a fairly good guideline when dealing with large populations, but on occasion fails miserably when dealing with individuals.

Let me give you some examples where this guideline may fail.

1. If an extremely fit Body builder were to enter his numbers in a BMI calculator it is quite possible for this individual to come up with a BMI indicating that he is obese.  The algorithm does not account for the fact that this individual has a body fat percentage of 7% and has more muscle then is normally found on a person. The bottom line is that it may overestimate body fat in athletes and others who have a muscular build.

2. If a 70 year old were to enter their data they may register as normal weight, but in fact be overweight because they no longer have the muscle mass they once did.  To say it differently BMI may underestimate body fat in older persons and others who have lost muscle.

3. Kids need a calculator aimed at kids and even then they all grow at their own pace so using a child BMI calculator to judge an individual child may be problematic.  Further info on BMI for children and teens.

BMI limitations aside setting an initial goal weight equal to a BMI around 25 is a good target for most folks.  After you reach that goal then you might want to fine tune your goal for a specific body fat percentage or fitness level.

The reason I am talking about this today is because every time I enter in my weight into my app it lists my BMI next to my inputted weight and then states in simple terms Obese Class II.  Well today when I entered in my weekly weight it changed to Obese Class I. I am celebrating that milestone and looking forward to hitting my next goal of losing my second ten pounds.

I estimate I'll have to get down to around 224 lbs before it stops referring to me as Obese and starts referring to me as simply overweight.  I can hardly wait.

So as you can see my current weight is 261.4 lbs making my weekly weight loss 2.2 lbs and my running total is now 18.8 lbs.  Talk to you all in another week.

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