BMI and fat loss

Posted on January 19, 2012. Filed under: Uncategorized | Tags: , , , , , , , |

If you have 1 lb of fat and 1 lb of muscle which weighs more?


Recently I did my presentation on fat loss.  and a question was asked in regards to the Body Mass Index (BMI).


Now biases upfront I am not the biggest fan of the BMI.  Mainly because according to this statistic I am obese.


Yep that’s right I am obese, and have been overweight for years apparently, who knew.


However, much like  somtatotypes (endomorph, ectomorph).   I am a big believer that before you can critique something you must understand what it is and where it came from.  So a quick history lesson.


In the 1830’s  a Belgian polymath named Adolphe Quetelet created this equation to define the “normal man”.


His study had absolutely nothing to do with obesity-related diseases, since in the 1830’s most had manual labor jobs and thus obesity was the furthest from their minds as a concern.  Heck, it was probably the goal of most.


Quetelet used the equation to describe the standard proportions of the human build—the ratio of weight to height in the average adult. Using data collected from several hundred men, he found that weight varied not in direct proportion to height, but in proportion to the square of height.

So a man who is 10% taller than another man wasn’t automatically 10% heavier, more like 20%.


Now I am sure some doctors had the idea that being too big, wasn’t very healthy.  But the BMI didn’t really race to the forefront till after Quetlet was long dead.   and who made them popular.  Insurance companies.


Insurance companies began using comparisons of height and weight among their policyholders to show that “overweight” people died earlier than those of “ideal” weight. Subsequent actuarial and medical studies found that obese people were also were more likely to get diabetes, hypertension, and heart disease.  Personally I think it’s more so the opposite way around.  That’s for another blog though.


I’m sure we can all agree that carrying too much fat is not good for your health.  As such the BMI was accepted as a method to determine  how much excess body fat people had. would it have been better to actually measure bodyfat percentage, yes. Accurate data for such a thing though is hard enough to get today let alone in the early 1900’s.  So they went with what was easier to track height, weight, and sex.


Insurance tables give correlations between these physical characteristics and expected lifespan. But medical researchers needed a standard measure of fatness, so they could look at the health


It was actually physiology professor and obesity researcher Ancel Keys who published his “Indices of Relative Weight and Obesity,” who established Quetlet’s equation as the most efficient. And Keys renamed this equation the body mass index.


In his day, Keys was a very influential figure.  And thus soon BMI became the standard by which all doctors would abide by.  For more interesting views on how Key’s influenced medical standards I recommend the documentary, Fat Head.  Fair warning, if you are a vegetarian or vegan, this will not be your favorite movie.  But if you keep an open mind you do gain some perspective from it.


To be fair Keys did warn against using the body mass index for individual diagnoses, since the equation ignores variables like a patient’s gender or age, which affect how BMI relates to health.


It’s one thing to estimate the average percent body fat for large groups with diverse builds, Keys argued, but quite another to slap a number and label on someone without regard for these factors.  The cat however was already out of the bag and running across the country side.


I have no idea why I used that analogy.


Any way, BMI was quick easy and because excess body fat was a rare occurrence on the average.  It seemed ok.  Keep this in mind research geared toward fat loss has been done in the last 10 or so years.  Prior to that it’s more so about weight loss.  Although certain studies do mention a difference in fat weight.  they are just few, far between and really annoying to track down, trust me.


So should we ignore BMI?  Not necessarily.  We just shouldn’t bother calculating it.   Let me explain.


Naturally speaking, it is very rare to find a guy who is 6 ft tall, 200+ lbs and lean.  If he is, he did it on purpose and has built his body to that point.  There is a limti though for any person how much they can take.


I don’t care if you are lean or not.  If our 6ft guy is +230 lbs, it is pretty obvious he is a big guy and that it is not healthy.  Think of it this way.


If I took the engine from a car like this:

Anybody else remember the original Herbie?

and put it in to this truck.

How long do you think the engine would last?


Being too big, is not healthy for any one.  and does have health concerns.  In my humble opinion though, the only factor BMI should play is in ths structure of a work out routine.


If I have a new client who is larger than average and I know has not done any kind of activity, I am not going to try to elevate their heart rate to quickly.  I don’t want to overstress the “engine.”


Over time as they get better conditioned I can progress the intensity and the volume.


Now if you are starting for a larger body mass point this is not an excuse to not work hard.  It is merely a caution of not overdoing it from the get go.  Listen to your body.


And if you are not sure how to do that.   Find a professional fitness coach, and listen to them

please note: If the coach can't at least give you a written framework of your workout plan for the next 3 months. They are not a professional.



Keep Fitness Groovy

Coach W


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[…] I am not suggesting it’s a good idea to carry an excess amount of fat on the body, or an excessive amount of weight for that matter. But the idea that we are in an obesity epidemic is ridiculous and unfounded by any […]

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