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Body Mass Index
marcmay posted:
I consider myself fit. I work out 6 days a week (run 5 miles six days, lift weights 3 days). I eat healthy, with a vice for coffee. In looking at the body mass index, I am considered overweight by their calculator. I am 5' 9" and weigh 170 lbs which is right on the cutoff between the overweight/ideal weight categories.

My question is, does the BMI (body mass index) take into account for those carrying more weight on their frame because of muscle versus fat?
3point14 responded:
Not at all, which is one of many flaws of using the BMI system to judge "healthiness".

Keep up the great workouts!
JKhealth responded:
I've read many places that a better indicator than the scale is that your waist size should be half your height. So at 5'9", your waist size should be 34.5 inches.

That's the goal I'm working toward.
JKhealth replied to JKhealth's response:
By the way, that's the waist size at your belly button should be half your height.
flightmedic1 responded:
My personal problem with the BMI calculation is that it does not take into account individuals with growth disorders, such as hypochondroplasia or achondroplasia. When seated, I am at eye level with many people, yet when I stand up I am a good 4 inches shorter than them.

The waist-to-height ratio is also skewed against those of use with limbs that are short in comparison to the "norm".

I'd be interested to know if anyone has heard anything concerning this.
Antler53 responded:
BMI, as many models in the health field are, is an ideal representation of what someone should weigh/look like. The model was based on a bell curve of data suitable to the greatest number of people who fit into certain categories. Without being too technical, while one person may be 5'7" tall and 170 lbs., there may be more individuals who are 5'7" tall and 155 lbs - which may be more ideal based on the data of the BMI model. So, in short, don't fret that you fall on the line between overweight and ideal.

A method of determining overweightedness which I like, and is rarely used due to the technical skills to adminster it, is the Heath-Carter model of human anthropometry. Developed at San Diego State University by Lindsay Carter, the model takes into account fat weight, muscle mass, and bone girth. Based on a number of measurements, you get a very accurate estimate of where you fall in terms of 'ideal' for your height and weight. We are all different and the thing that BMI does, which unfair to the masses, it is a `quick and dirty`measurement of the RELATIVE body mass to height - it does not account for bone girth.. Doctors gravitate toward it for the reason it is easy to administer and shows those patients who are grossly overweight, where they relatively stand when compared to others. It is a motivational tool - that is all!
An_245796 responded:
I think it is a useful tool to see where you are if you are a sedentary person or someone starting out. One of many factors the BMI does not take into account muscle mass. For instance I am in between 5'9 and 5'10 and I weigh 178 which puts me around 26. But I do a lot of strength training.
Pamela Peeke, MD, MPH, FACP responded:
Hi and thanks so much for your posting. Marc you ask a great question. Here's what you should do. Have your body fat % checked. Real easy. Buy an inexpensive body fat scale. Or go to the gym and have an experienced trainer measure you. For a guy, your body fat % should be in the range of 16-22%. The younger you are, the closer you are to the lower number. If you're in that range you're fine.

BMI is weight divided by height in meter squared. It doesn't take into account your body composition. We are docs and scientists have simply used the BMI to measure disease risk.

I'd stick with body fat % and don't worry about the BMI. Sounds like you're doing well and congrats for that!

Dr. Peeke

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