Monday, November 16, 2009

A Healthy BMI

What’s a healthy weight goal for you? In the last 10 or 20 years, health experts have changed that question to what is a healthy body mass index (BMI) for you? The BMI takes into consideration the amount of bone, muscle and fat in your body’s composition and is considered better than the more straightforward height and weight charts that insurance companies used years ago.

I’ve heard that those old charts said a woman should weigh between 3-5 pounds more than a 100 for each inch above five feet tall, so a 5’6” woman should weigh between 118 and 130 pounds. The newer BMI measure would say a 5’6” woman who weighed 118 was underweight.

There are easy ways and hard ways to measure BMI with the harder ways being more accurate but also requiring much more expensive technology. An easy way to calculate your BMI is a formula based on your weight in pounds and your height in inches.

BMI = (Weight in Pounds X 703) / (Height in Inches X Height in Inches)

The calculation for a 5’6” woman who weighed 140 (alas, not me!) would look like this:

22.59 = (140 X 703 = 98,420) / (66 X 66 = 4356)

A BMI between 25 and 29 is considered overweight while anything 30 and above is obese. Below 20 is underweight, and 20 to 25 is healthy.

Honestly, the formula results seem on the high side based on the results I’ve seen online from BMI calculators that take into account other measurements, but it may assume the woman is not very fit with a lack of muscle tone. (Or, I’m deceiving myself.) One online BMI calculator I like is on Body by Glamour, and I highly recommend you try that one.

You also can see some of the more accurate but also more expensive ways to measure BMI in the first episode of many of The Biggest Loser seasons. I believe one test measures the amount of water displaced when you get into a tub. I’ve never met anyone who got their BMI measured with one of these methods, but it could be an interesting exercise.

Weight Watchers now stresses a healthy BMI. Their healthy weight ranges are based on BMI but easily translate to a height/weight chart.

Height Weight (BMI = 20) Weight (BMI = 25)

4’9” 92 116

4’10” 96 120

4’11” 99 124

5’0” 102 128

5’1” 106 132

5’2” 109 137

5’3” 113 141

5’4” 117 146

5’5” 120 150

5’6” 124 155

5’7” 128 160

5’8” 132 164

5’9” 135 169

5’10” 139 174

5’11” 143 179

6’0” 147 184

6’1” 152 189
6’2” 156 195

6’3” 160 200
6’4” 164 205

6’5” 169 211

I can’t imagine thinking a 6’2” man weighing 200 pounds is overweight, but these are interesting guidelines to look at as you figure out what’s a healthy weight for you. I’m using the healthy BMI range as my ultimate goal in my weight loss journey. I’d like to get back into that range with perhaps a 10 to 20 pound cushion. I’m around 5’6”, and my healthy weight range is 124 to 155 or a BMI of 20 to 25. I’ve been throwing around the 135 to 140 pound range as my ultimate goal. That may be too ambitious, but I may get there if I keep working at it.

What do you think of the body mass index? Do you think it’s more accurate than the old height weight charts or a new way to talk about the same old thing? Does it influence what you think is a healthy weight for you?


Elise Hayes on November 16, 2009 at 8:53 AM said...

I do think the BMI target is a lot better than the old height/weight charts (although I still think the BMI charts don't account enough for muscle mass)

I remember way back in grad school, when I was working out 6-7 days per week (running 20-30 miles per week, playing Ultimate frisbee, doing 2-3 hour rock-climbing sessions at the rock gym three times a week), I went in to the health center for a check-up. I was covered by one of those paper gowns. The doc walked in looking at my chart, didn't look at me (not that he would have seen anything through that gown) and said, "'re probably not going to want to carry this much weight when you're older." (Note, if they'd been using BMI back then, I would have been around a 22 or 23)

I was shocked. And a smiliar thing happened to another friend of mine who was an insane athlete (this more recently, while she was living in France. Maybe they don't use BMI there?). Those old charts just didn't account for muscle weight.

Maybe the docs approached men differently--but this story has been too common among women athletes I've known.

Michelle Butler on November 16, 2009 at 10:15 AM said...

It may be that to get a true evaluation of muscle mass, you have to do the highly accurate but expensive BMI testing. I don't know how one would arrange that - probably through sports and sports injury doctors?

I also think there's still a lot of debate in the medical and scientific communities about what is a healthy weight. I've heard there was a recent study that said being slighly overweight may be healthier (in terms of living longer) than being a healthy weight. It kind of boggles the mind.

I do think that athletic/muscle bound guys can have hard times with these charts too. A good friend of mine was an Air Force JAG for several years and had to pass a fitness exam annually. She doesn't like exercise, so I loved to hear how she approached it. It turns out that there is some kind of point system based on a lot of measurements. She is a petite woman of Asian descent so she always rocked the waist measurement portion. It got her so far ahead of where she needed to be that she always entered the running portion knowing exactly how hard she had to push herself to pass. She didn't have to push herself much at all.

She did say that the Air Force was reevaluating this system because big, very fit, very muscular guys might not pass and be put on what my dad always called affectionately the fat boy program. (He's retired from the Air Force - and speaks very affectionately of the 60's when the USAF didn't make you exercise at all or care about fitness - and he didn't have to worry about the fat boy program.) Anyway, the current system is not fair to the muscular, big guys.

It could be that figuring out what a healthy weight is is really evaluated best as a case-by-case basis. I'm using the BMI range to try to be healthy about it. Otherwise, I might get stupid and want to be 115 pounds like I was as a freshmen in high school - that's obviously whacked. I also pay a lot of attention to clothes sizes.

Elise Hayes on November 16, 2009 at 11:38 AM said...

I think BMI can be really helpful in terms of establishing healthy goals for yourself. I've had friends in the past who have lost a significant amount of weight and who went a little body-image crazy for a few years afterwards. One friend in particular just fixated on one body part that seemed to her to be bigger than what she wanted--even though she went down to a size 4!--and she kept trying to lose more weight to target that area. That's definitely not the way to go...

Michelle Butler on November 16, 2009 at 7:58 PM said...

I'm sure I'll struggle with body image issues as this progresses, but I'll try to be aware of it and not get too whacked out.

Tawny on November 16, 2009 at 8:47 PM said...

I think that BMI, like the number on the scale, is just that- a number. Its a good ballpark to aim for, but I don't think its a true picture of actual health. That said, I do use it as a goal number to strive toward :-)

Michelle Butler on November 16, 2009 at 9:00 PM said...

I did realize that this post was an interesting contrast to last week's - what's in a number? Like you, Tawny, I just find the BMI a useful number to work towards. Honestly on a day-to-day basis, I find it more rewarding and helpful to think about and work towards getting into the next clothes size down. This also can address all the progress we're making through exercise.

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