Is BMI bunk?

[cantdrv55]

According to a BMI calculator, I have a BMI of 33 which puts me in the obese category. So, I played around with the numbers to determine what my weight would have to be to be in the upper end of "normal". The calculator said I have to lose 70lb or get down to 150lb! Unbelievable. I haven't been 150 since high school and when I look at old pics of me in HS, I looked gaunt. I remember feeling at my best health when I weighed 185. The BMI calculator said I'd be overweight, close to obese at that weight. Is BMI bunk?

[Geronimo '74]

You're not to fat, most likely you're just not tall enough for your weight...


A BMI of 33 is high, too high probably.
For an average person it is a good indication to see if you're overweight or not.
But is just a comparison between height and weight. ( e.g. bodybuilders will have a high BMI with only 4-5% bodyfat!)

Other measurements will tell you more:
What is your overall fat percentage?
This is a more precise indicator.
Best to have it tested in a gym or at the doctors.
Body Fat Calculator 6 formulas calculate your body fat percentage

Values for men:

Essential fat 2-4%
Athlete 6-13%
Fitness 14-17%
Acceptable 18-25%
Obese 25+%


EDIT: or buy one of those scales that measure fat%, I forgot about those. They're more than accurate enough for most people's needs.

[aap1966]

Statistically, for someone of European descent a BMI > 30 (Asian > 28, Polynesian >32) carries an increased risk of premature cardiovascular disease, (Heart attacks, strokes), Maturity Onset diabeties, and a number of cancers, e.g: cancer of oesophagus, bowel, pancreas, kidney and (yes, even in men) breast cancer.

Those are the stats.

[IROC]

BMI only has marginal value. Muscle mass can really throw off the numbers. Many (most? all?) NFL running backs have BMIs in the 30s. IIRC many studies have shown that life expectancies are greatest for people with BMIs in the 25-30 range - contrary to the fact that this range puts one as "overweight".

Overall health is much more important than a BMI number for sure.

[Tobra]

BMI is a gross measurement that does not take into account that muscle is heavier than fat. Had a buddy at Oregon State who was doing a paper on BMI and % body fat. At the time, I was doing a lot of cycling, thighs bigger than waist. My % body fat was less than 10, BMI greater than 30. According to the BMI thing, at the time I was morbidly obese.

BMI is bunk

[Rick Lee]

When I was in my best, marathon-running shape, the BMI chart said I was obese. That's when I stopped caring about BMI at all.

[jyl]

Sounds like the better measure is body fat. You can get step-on scales that measure body fat through your body's electrical conductivity.

[Embraer]

BMI is Bunk. In college I was 7% body fat, 190lbs, and I'm 5'8" I had a 28in waist and 46in chest.

[TechnoViking]

You can buy one of those scales that will tell you your % body fat for about $60 at Target, Wal Mart, etc.

The scales aren't perfect, but I like the idea of measuring % body fat a lot more than BMI.

[jyl]

That said, most of us are not body builders, marathoners, bike fiends - indeed, none of the "BMI = bunk" folks posting on this thread are either, they only used to be and that was decades ago.

My guess is that for the average person, and most of us are pretty average, physique-wise, BMI is not a bad proxy for body fat.

Let's put it this way - if your BMI reads around 30-35, your body fat is probably a good bit higher than you'd like - 30%-ish. Measure body fat if you can, but if you only have BMI, then don't dismiss it as bunk unless you truly do have a remarkable amount of muscle.

[M.D. Holloway]

Your just big boned

[Tobra]

You are mistaken John.

Right now, according to that BMI nonsense I need to lose about 30 lbs. I would be willing to guarantee that my % body fat is under 15, and I am no body builder. BMI is used because it is a simple to obtain, height and weight. It is a misleading and mostly worthless metric, particularly for someone who is the least bit lean.