Posted on 09/17/2020 8:59:38 AM PDT by Red Badger
Robert H. Shmerling, MD Senior Faculty Editor, Harvard Health Publishing
Do you know your BMI? Increasingly, people know theirs, just as they know their cholesterol.
If you don’t know your BMI, you can use a BMI calculator available online, including this one at Harvard Health Publishing. All you need is your height and weight. Or, you can calculate it yourself, using this formula:
BMI = (Weight in Pounds x 703) / (Height in inches x Height in inches).
So, now that you know your BMI, is it worth knowing? What are you going to do with it?
What your BMI means
To understand what your BMI means, it’s useful to take a step back and understand what it’s measuring and why it’s measured.
BMI is a calculation of your size that takes into account your height and weight. A number of years ago, I remember using charts that asked you to find your height along the left side and then slide your finger to the right to see your “ideal weight” from choices listed under small, medium, or large “frame” sizes.
These charts came from “actuarial” statistics, calculations that life insurance companies use to determine your likelihood of reaching an advanced age based on data from thousands of people. These charts were cumbersome to use, and it was never clear how one was to decide a person’s “frame size.”
BMI does something similar — it expresses the relationship between your height and weight as a single number that is not dependent on “frame size.” Although the origin of the BMI is over 200 years old, it is fairly new as a measure of health.
What’s a normal BMI?
A normal BMI is between18.5 and 25; a person with a BMI between 25 and 30 is considered overweight; and a person with a BMI over 30 is considered obese. A person is considered underweight if the BMI is less than 18.5.
As with most measures of health, BMI is not a perfect test. For example, results can be thrown off by pregnancy or high muscle mass, and it may not be a good measure of health for children or the elderly.
So then, why does BMI matter?
In general, the higher your BMI, the higher the risk of developing a range of conditions linked with excess weight, including:
diabetes
arthritis
liver disease
several types of cancer (such as those of the breast, colon, and prostate)
high blood pressure (hypertension)
high cholesterol
sleep apnea.
According to the WHO, nearly 3 million people dye yearly worldwide due to being overweight or obese. In addition, independent of any particular disease, people with high BMIs often report feeling better, both physically and psychologically, once they lose excess weight.
And here’s why BMI may not matter
It’s important to recognize that BMI itself is not measuring “health” or a physiological state (such as resting blood pressure) that indicates the presence (or absence) of disease. It is simply a measure of your size. Plenty of people have a high or low BMI and are healthy and, conversely, plenty of folks with a normal BMI are unhealthy. In fact, a person with a normal BMI who smokes and has a strong family history of cardiovascular disease may have a higher risk of early cardiovascular death than someone who has a high BMI but is a physically fit non-smoker.
And then there is the “obesity paradox.” Some studies have found that despite the fact that the risk of certain diseases increases with rising BMI, people actually tend to live longer, on average, if their BMI is a bit on the higher side.
Should we stop giving so much “weight” to BMI?
Maybe. There are studies suggesting that BMI alone frequently “misclassifies” metabolic health. For example, found that:
More than half of those considered overweight by BMI had a healthy “cardiometabolic profile,” including a normal blood pressure, cholesterol, and blood sugar.
About a quarter of people with normal BMI measures had an unhealthy cardiometabolic profile.
Actually, this should come as no surprise. BMI, as a single measure, would not be expected to identify cardiovascular health or illness; the same is true for cholesterol, blood sugar, or blood pressure as a single measure. And while cardiovascular health is important, it’s not the only measure of health! For example, this study did not consider conditions that might also be relevant to an individual with an elevated BMI, such as liver disease or arthritis. In addition, more recent studies (such as this one and this one) suggest that those who are healthy and overweight or obese are more likely to develop diabetes or other negative health consequences over time.
Bottom line
As a single measure, BMI is clearly not a perfect measure of health. But it’s still a useful starting point for important conditions that become more likely when a person is overweight or obese. In my view, it’s a good idea to know your BMI. But it’s also important to recognize its limitations.
ECTOMORPH, ENDOMORPH AND MESOMORPH?..............
Oops, the ratio should be less than 0.5.
It kept me off the fat boy program in the military.
Suck in your gut and puff out your neck and it's easy to pass.
” I would expect width and thickness to increase by 10% also for a total weight increase of 33%. “
V = Pi * r^2 * h
I was in the Marines back when they first started using BMI as a measure to determine if you were ‘obese’.
We had a guy in our company that was a body builder. He was a short person, probably 5’ 3 “ or so.
He was in no ways ‘fat’ or ‘obese’, but his BMI said he was.
They made him go to what we called ‘Fat Body Platoon’ three times a week, afternoons.
He loved it.
He got to exercise and jog and lift weights and it got him out of ‘work’!....................
It’s not the fat that kills you, it’s the things that put the fat there that does.
As Dr. Berg said, You don’t lose weight to get healthy, you get healthy to lose weight.
The BMI calcs were probably written by a doctor from Somalia
Know a girl. I say girl because she is 30 years younger than me but whatever. Anyway. Big girl, very pretty, but overweight. Wanted that lapband surgery, stomach surgery to lose weight. Dr. wouldn’t do the surgery until her BMI was over 30...32, whatever. She is a nurse. She was just short of 30. So, she ate herself over 30, went back to the DR. and got her surgery. Lost over 100 lbs. pretty quick.
I don’t know why she couldn’t have just quit eating so much and excercised some but it worked for her....!
Or a Jenny Craig stockholder....................
All she had to do was eat hospital 'food'...................
It was noted when BMI came out that their formula would have declared Shaquille O’Neill, during his playing career with the Lakers, as “morbidly obese”.
I reject “one size fits all medicine”, particularly that foisted upon us by government-run health organizations. The whole COVID debacle is proof that they often don’t know what they’re talking about.
BMI is useful when dealing with people who don’t have a significant amount of extra muscle. So for the vast majority of the US population, it works just fine. For those who do build extra muscle, it’s not useful. That’s when a doctor should be taking a more individualized approach to that person’s fitness and health.
The modern term BMI was coined in a 1972 paper, the same year Shaquille O’Neal was born.
And yes, for athletes who build significant muscle mass, it’s not an accurate gauge. For the general public, which has very little muscle, it actually works pretty well as a short-hand.
BMI is totally stupid. It measures nothing. People are not just different heights. They are different thicknesses as well. BMI assumes that everyone is the same muscle mass, and bone mass. Totally false.
And men and women should weigh the same
Look at a 100 Meter sprinter and a 5000 meter runner. Their BMI is very different but neither has any fat. The decathlon athlete has an even higher BMI with no fat.
lol
It’s one of those arbitrary metrics that have become truth because it is repeated so often — largely by people who don’t know any better, because all they’ve ever learned in life, is what somebody told them to repeat. “Hey hey, ho ho...” as though that made them sound intelligent and united.
In the case of the “BMI,” “target heart rate,” “cholesterol,” it was sold as the “correct” answers to the idiotic tests to become certified as “fitness” instructors — at their one-day seminars for obtaining their certifications, which also required a “First Aid and CPR” certification as a prerequisite — for which they are simply certifying that one possessed it on admittance, and not that it was truly an expertise in anything beyond that.
That is the obvious example of abuse of these certifications of truth. There’s actually no scientific substantiation — but people quote the “experts” — because they have no idea that the “scientific method” requires validation by anyone — and not simply repetition of unquestioned, and unchallenged truths.
That is the quintessential scientific method — that it can be challenged at all times, by anyone — and not just the authoritarianism of those whose main achievement in life is rising to the position of greatest prominence — often by ruthlessly suppressing all other explanations. Thus the popular media preens itself on its ability to convince us of what is untrue as their own display of power in determining who are these authorities — just like the ancient “Pharisees and Scribes,” Jesus often referred to — as self-anointed authorities on virtually everything.
The BMI can be calculated from the original tables — just as the tax rate algorithm simulate the tax tables — but that doesn’t make it sacrosanct. The Target heart rate is a similar arbitrary calculation — mainly to sell heart rate monitors. The aversion to cholesterol has no scientific basis other than a few conjectures and deeply flawed epidemiological studies that merely confirmed what the proponent “wanted” to prove. That’s not science — even as much as it is repeated as the Golden Rule to Health either. In fact, that may be the cause of most age-related diseases of the metabolic kind — in that the brain and all the organs are actually composed of cholesterol and fats — because they are insoluble in water, and thus compose the cell walls, and when they break down, wreak predictable havoc on the rest of the body.
So when I hear someone boasting of knowing “BMI,” “Target heart rate,” “high cholesterol,” I immediately recognize that that is the extent of “all” they know — and nothing else of true significance.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.