Why is the BMI equation needlessly complex?

[air2fakie]

Ha, nice F&F reference.

And fair enough, given that the "measure" itself is rather vague and hard to arrive at precisely. As far just going off of what you see in the mirror, however, I for one totally thought I was less fat than I was a couple of years ago, possibly even last year. It might still be best to get an honest opinion from someone else since there's no objective way of seeing through one's own delusions. In lieu of that and in that regard, waist/height probably still is the best way to go.

Sure I guess in the end I think it's all a matter of personal preference and how one looks IRL, which I don't think these metrics (or attempts to measure them) capture.

For ex, if you thought you looked like a lean, juicy piece of meat does it really matter if you were fatter than you thought or what your BMI was?

Plus even though the forums are mostly male, the BMI/bf% metrics apply to females too (even if adjusted). And women can look much more diff from each other whether at the same number or at diff ranges, based on general shape, where curves are, muscle, etc. The mirror is the only useful measure.

I find it weird when people post pics and ask what their bf% is, so they know they can bulk if they've reached 12%. They care less about what they're seeing in the mirror and more about what random people think their bf% is.

[paulinkansas]

It might still be best to get an honest opinion from someone else.

Run the Dickie Do test I mentioned earlier and post your observations here. You'll get several opinions.

[EiFit91]

For ex, if you thought you looked like a lean, juicy piece of meat does it really matter if you were fatter than you thought or what your BMI was?

All good points in your post (particularly agree on the point about bulking and unnecessary BF% obsession), I just couldn't help myself lol

[snailsrus]

I think bmi can tell you if your really under weight or really over weight. Then again so can a mirror

[Darkius]

That's not what I mean.

I mean why can't it just be: weight/height

instead of weight/height(m)^2 ?

Both are wrong. It should be weight/height ^3. Mass is proportional to volume, not height. At least their equation is less wrong than yours. It classifies more short fat people as healthy and more tall thin people as obese.

[AdamWW]

Both are wrong. It should be weight/height ^3. Mass is proportional to volume, not height. At least their equation is less wrong than yours. It classifies more short fat people as healthy and more tall thin people as obese.

uhhhhh....

[desslok]

uhhhhh....

IMO they should just have a box similar to what the airports have to see if your bags fit. If you can get into the box you are a good BMI(box MI). If 2 of you can fit in the box you are too thin. If you don’t fit in the box then you need to pay for two tickets.

[Darkius]

uhhhhh....

Ok, you want single dimention:

If your waist is less than half your height, you are fine. If larger, then you need to lose fat.

Women have larger hips and smaller waists than men, so their allowable waist is 0.9 that of men's.

[air2fakie]

Ok, you want single dimention:

If your waist is less than half your height, you are fine. If larger, then you need to lose fat.

Women have larger hips and smaller waists than men, so their allowable waist is 0.9 that of men's.

Dementia is the appropriate word. What does this have to do with what you just said earlier?

[paulinkansas]

Never criticize a person until you've walked a mile in their shoes. Then you'll be a mile away from them and have their shoes.

Then you can do what I did to one of my room mates. I put their shoes in the freezer when they went to sleep at night. The next morning, they had to wear frozen shoes.

[desslok]

Then you can do what I did to one of my room mates. I put their shoes in the freezer when they went to sleep at night. The next morning, they had to wear frozen shoes.

Thats cold…

[AdamWW]

Ok, you want single dimention:

If your waist is less than half your height, you are fine. If larger, then you need to lose fat.

Women have larger hips and smaller waists than men, so their allowable waist is 0.9 that of men's.

You didn't even provide units of measurement.

Did you attend grade school?

[desslok]

You didn't even provide units of measurement.

Did you attend grade school?

If you hold up a pair of your pants, you should be able to just wrap the waist part around your neck and have a snug fit.

[AdamWW]

If you hold up a pair of your pants, you should be able to just wrap the waist part around your neck and have a snug fit.

[RapidFail]

The BMI equation is actually needlessly simple. A simple height:weight ratio doesn't work at all for reasons addressed by other posters. BMI works reasonably well for people of average height and muscle, but it could be better.

The reason BMI uses height to the power of 2 is because it was created in the early 19th century, when most people did not have access to a calculator. The link below provides a better BMI formula, which uses height to the power of 2.5 along with some adjustments to make it fit the same scale as normal BMI, i.e. , under 18.5 is underweight, 18.5-25 is normal, 25-30 overweight, 30+ obese.

https://people.maths.ox.ac.uk/trefethen/bmi_calc.html

[air2fakie]

The BMI equation is actually needlessly simple. A simple height:weight ratio doesn't work at all for reasons addressed by other posters. BMI works reasonably well for people of average height and muscle, but it could be better.

Isn’t the whole point of this type of index so it works reasonably well for people of all different heights and “muscle”?

[desslok]

Isn’t the whole point of this type of index so it works reasonably well for people of all different heights and “muscle”?

I think it worked better 100 years ago or whenever it was invented, before the obesity epidemic and before bodybuilding was a thing. Nowadays, these 2 “outlier” groups are becoming the norm.

[RapidFail]

Isn’t the whole point of this type of index so it works reasonably well for people of all different heights and “muscle”?

The link I provided gives an alternative formula that gets rid of the height problem with BMI, but the same problem for people with lots of muscle exists. Not sure what the work-around for that would be.

[joewattie]

The link I provided gives an alternative formula that gets rid of the height problem with BMI, but the same problem for people with lots of muscle exists. Not sure what the work-around for that would be.

Go figure. Using the new calculator I went from chubby to chubbier! Or maybe I went from muscular to more muscular? So, perhaps, chubby BMIs (25+) should simply be viewed as a badge of honor for weight lifters? It's like ... you've arrived!

[EliKoehn]

I think it worked better 100 years ago or whenever it was invented, before the obesity epidemic and before bodybuilding was a thing. Nowadays, these 2 “outlier” groups are becoming the norm.

That's an interesting point - it makes sense that obesity has been normalized because of the "path of least resistance" afforded by modern civilization, but so has bodybuilding, as an expectation in the alternative. I'm definitely affected, but I doubt average people, say in the middle 20th century, had anxious desire to be more than reasonably muscular or lean - in fact leanness might still not have been deliberately sought after.

[air2fakie]

The link I provided gives an alternative formula that gets rid of the height problem with BMI, but the same problem for people with lots of muscle exists. Not sure what the work-around for that would be.

Yeah wasn't blaming you for it. :P Just think an "index" that's supposed to be an indicator of health should be more universal. You don't have to be a pro bodybuilder for the index to be total bs.

[paulinkansas]

Formulas and equations can have origins that have nothing at all related to their purpose. The 2 guys that developed the Black Sholes option pricing model won the Nobel prize in economics for developing it. An option is a financial instrument used for buying or selling an underlying security. The model was based on a physics equation for heat transfer. I was in grad school when they got the Nobel prize. The class syllabus was changed in order to teach the model.

[EliKoehn]

Formulas and equations can have origins that have nothing at all related to their purpose. The 2 guys that developed the Black Sholes option pricing model won the Nobel prize in economics for developing it. An option is a financial instrument used for buying or selling an underlying security. The model was based on a physics equation for heat transfer. I was in grad school when they got the Nobel prize. The class syllabus was changed in order to teach the model.

How does it have nothing to do with economics, just because it was also useful for physics?

EDIT: Whoops, you said "origin." I will let the retarded question stand, however.

[paulinkansas]

How does it have nothing to do with economics, just because it was also useful for physics?

EDIT: Whoops, you said "origin." I will let the retarded question stand, however.

I developed a formula for perceived masculinity in public a long time ago. The variables were the number of women you were with. The ideal number is 2. More than 2 and you look effininate. 1 is just average. 0 is below average.

Think about it, you're out in a bar with 2 attractive women. What are all the other guys thinking of you?

[EliKoehn]

I developed a formula for perceived masculinity in public a long time ago. The variables were the number of women you were with. The ideal number is 2. More than 2 and you look effininate. 1 is just average. 0 is below average.

Think about it, you're out in a bar with 2 attractive women. What are all the other guys thinking of you?

Chase two and you lose both, is what I'd think.

[paulinkansas]

Chase two and you lose both, is what I'd think.

The 2 ladies I was with were sisters in law and liked to party. Nothing happened though, but years later I found out something could have.

[paulinkansas]

The masculinity formula is M = N/(N-2) where N is the number of women you are with.

[EliKoehn]

The masculinity formula is M = N/(N-2) where N is the number of women you are with.

So if you're with 2 women, you have to divide by zero?

The Cournot equilibrium shows no change in the long-run. I see this is an economic model.

[SuffolkPunch]

The masculinity formula is M = N/(N-2) where N is the number of women you are with.

So... if you with 2 women... infinite masculinity?

Also:

[desslok]

I developed a formula for perceived masculinity in public a long time ago. The variables were the number of women you were with. The ideal number is 2. More than 2 and you look effininate. 1 is just average. 0 is below average.

Think about it, you're out in a bar with 2 attractive women. What are all the other guys thinking of you?

SNL had a great way to find masculinity as well:

Quien es mas macho:
https://vimeo.com/365899455