Bmi

[TriDove]

According to my BMI I am overweight, this makes me feel like crap but I am questioning whether this really means I have to lose weight... Let me explain in numbers: I'm 6'7" tall, weigh 230lbs, have a 36" waist, have a large chest, broad shoulders and reasonably defined muscles. If I asked someone on the street they'd probably say I was slim, and yet I'm technically overweight.

I mean I have some slight chub on my love handles that I'm currently working to get in check for the summer, but I can hardly imagine they weigh the 10lbs I would be required to lose to get back in a healthy weiht range. So is it true? Do those numbers I've listed suggest I might have a higher than average risk for all those weight associated ailments or is this just BMI failing the tall?

 

[theGOOCH]

I don't agree with a one size fits all chart to determine obesity. Dennis Rodman at least in his prime ws your height and weight almost exactly.

Here's an argument I found on the net...anyone have any comments?(I think the first example is bad because in most cases a 6foot 270 lb. person is obese).

BMI ignores the square-cube law.

Example: 3 foot tall, 35 pound four-year-old) has a BMI of 19.0 - just barely out of "underweight" range. A 6-foot tall person person, who weights 270 pounds (doubling the linear size should multiply weight by 8 assuming the exact same bone-to-muscle-to-fat ratio) has a BMI of 36.6 - morbidly obese.

Example 2: A 5-foot tall, 100 pound model has a BMI of 19.5 (BMI says she's almost underweight; most of us would call someone built like that "solid" but not "fat"). Take that woman to 6 feet tall and BMI wants her to be 144 pounds to stay at a BMI of 19.5 - ignoring the fact that square-cube laws say that if you just "stretch" the 5-foot model in all dimensions she'll be 172 pounds.

In other words, to stay "not obese" you have to get skinnier and skinner as you get taller. NBA player Yao Ming, at 7-6, 310 pounds, is considered well in the overweight range by BMI (26.9, with anything over 25 being "overweight") even though we can all practically see the dude's bones through his skin. Shawn friggin' Bradley is on the heavy side of "normal."

Stupid.

 

[Chillen]

The BMI calculator on the internet says I am obese (26% BF) at 161lbs, 46, at 5' 7". Believe me when I tell you, I am not even close to that.

The BMI "can be" mobidly obsurd, and can stink like a turd.

What you need is "general" basic diet and fitness education, and by earning this in your head, will remove some of the feelings you are expressing about the BMI predictions. There are far too many variables in bone structure size and bodily construction in general, per person, to have BMI come close to being accurate (unless one is using a rather accurate method like DEXA, which is what I use).

Save yourself some pain, educate yourself. Then look at BMI calculators (such as the one's on the internet) through educated eyes. More importantly, if you choose to know what your BMI is, go get this "properly" performed through generally respected methods.

Education within diet and fitness CAN and WILL save one a lot of pain.The truth about diet and fitness will set one free.

DO IT!


Best wishes,


Chillen

 

[tjl]

According to my BMI I am overweight, this makes me feel like crap but I am questioning whether this really means I have to lose weight... Let me explain in numbers: I'm 6'7" tall, weigh 230lbs, have a 36" waist, have a large chest, broad shoulders and reasonably defined muscles. If I asked someone on the street they'd probably say I was slim, and yet I'm technically overweight.

BMI is most useful for population studies, where most people's "excess" weight is fat. People with good physical fitness may be "overweight" with muscle rather than fat, so they may have a high BMI but not be unhealthy. So BMI is not that good on an individual basis on the "overweight" end for someone with a reasonable amount of muscle (although it is possible for someone to be both highly muscular and overfat, BMI alone cannot distinguish between that situation, someone who is just overfat, and someone who is muscular but not overfat).

At 6'7" with a 36" waist, you waist / height ratio is 45.6%, where 50% or less is generally considered healthy and 45.8% is apparently what David Willoughby (a champion body builder) found to be the ideal male athlete waist / height ratio (see ). Note that Willoughby also lists the ideal athlete weight for your height at 259 pounds (cube of height divided by 1906), which would be a BMI of 29.2 (compared to your weight of 230 pounds or BMI of 25.9).

 

[Kraken]

I'll chime in to say this thing is a total farce.

I'm 6'-3" 215 with a 34" waist. Last time I had my BMI measured by a doctor it was 11.8%
According to that stupid online thing I'm morbidly obese. So don't worry about that crap. Get it measured by a professional for better accuracy.

 

[malkore]

BMI is a pretty useless number. a short anorexic woman might be 'healthy'...while a pro bodybuilder with 5% bodyfat would be morbidly obese.

height vs weight is a poor way to determine if you're too fat since it doesn't take into account ANY body fat percentage. Its just an arbitrary scale.

you're much better off knowing your bodyfat percentage, or just looking in a mirror.

 

[subdude]

BMI is basically the idiot's way of determining if someone is fat. But tjl raises a good point---BMI is useful for observing population trends. We pretty much know how much each person weighs and how tall each person is, but data on body fat % is a lot more scarce. So, if we want to compare obesity trends from state-to-state or year-to-year, we're sort of forced to look at BMI. And really, BMI probably does give us a good idea of obesity trends so long as the average person isn't getting taller or shorter and as long as the average person isn't building a lot of muscle. Assuming both conditions hold, BMI's weaknesses with regard to height and muscle/fat% are not consequential. And assuming that most people's idea of working out is cardio rather than weight training, BMI won't give us a false indication of a less healthy public if more people pursue a healthy lifestyle. Sure, a lot of people's BMIs increase when they start caring about their level of fitness (e.g., the scrawny high schooler who decides he wants to become a linebacker), but those people are the exception rather than the rule.

Beyond trends involving a lot of people, the BMI is, of course, garbage and not to be taken seriously.