@puzzlegal has started a dedicted thread on this:
I think this is a valid point. Scientists often seem to forget that the terms they come up to categorize people will have an effect on people. It probably would have been better if the BMI scale had more neutral terms about the ranges, such as numbers 1-5, rather than terms that have negative connotations like underweight, overweight, obese, etc. I think people would be more willing to accept their BMI results if it was specified as something like “BMI 2 up” rather than “obese”. No one wants to have the label of obese. Giving that label to people will cause them to try discount the system which labeled them that way. We can say we wish that’s not the case, but that’s just human nature.
As you mention, someone may shy away from exercise because they don’t want to gain weight and end up with the obese label. Even if it’s from muscle and stronger bones, they still don’t want to be called obese. I definitely agree that aspect of BMI can be counterproductive to helping people get healthier. Exercise is always beneficial regardless of whether your weight goes up, down, or stays the same. There are tons benefits to exercise that can help you have a better quality of life and longer lifespan that are completely independent of whether or not your weight changes.
BMI remains a useful tool providing a rough estimate of individuals’ risk of diseases related to being overweight and obese. It is not, and never was intended as an all-purpose guide to health.
No doubt there are people who oversell BMI’s usefulness, just as there are those who denounce efforts to reduce obesity as “fat-shaming”.
It’s important to differentiate cynicism* from conspiracy theorizing. Interventions aimed at establishing healthier weights do tend to lower insurance payouts and improve profits for insurers. They also benefit the insured.
*cynics might wonder what makes an emeritus professor of math known as “the Math Guy” an expert on obesity. The Emeritus Syndrome has claiimed an impressive list of victims.
They did, and they got it, making like a million American Obese
with the stroke of a pen.
How about a general Physical from your MD? If you are healthy, then your wight is not an issue.
Cite?
BMI is a height weight comparo, based upon 17th century peasants- I just want to point out- we are not 17th century European peasants- medicine today is many order of magnitude advanced form those days. The chart had to be changed, since of course, people over 6’ tall werent included much originally.
There’s just one problem: A higher BMI doesn’t necessarily mean you’re less healthy. In fact, patients with heart disease and metabolic disorders whose BMIs classify them as overweight or mildly obese survive longer than their normal and underweight peers. A 2013 meta-analysis by the National Center for Health Statistics looked at 97 studies covering nearly 3 million people and concluded that those with overweight BMIs were 6 percent less likely to die in a given year than those in the normal range. These results were even more pronounced for middle-aged and elderly people. This is known as the obesity paradox. “The World Health Organization calls BMIs of 25 to 29.9 overweight,” says Paul McAuley, an exercise researcher at Winston-Salem State University. “That is actually what is healthiest for middle-aged Americans.”… And get this: While epidemiologists use BMI to calculate national obesity rates (nearly 35 percent for adults and 18 percent for kids), the distinctions can be arbitrary. In 1998, the National Institutes of Health lowered the overweight threshold from 27.8 to 25—branding roughly 29 million Americans as fat overnight—to match international guidelines. But critics noted that those guidelines were drafted in part by the International Obesity Task Force, whose two principal funders were companies making weight loss drugs. In his recent book Fat Politics: The Real Story Behind America’s Obesity Epidemic, political scientist Eric Oliver reports that the chairman of the NIH committee that made the decision, Columbia University professor of medicine Xavier Pi-Sunyer, was consulting for several diet drug manufacturers and Weight Watchers International.
If someone is underweight by BMI they likely really are underweight. If someone is obese by BMI they likely really are over fat. In between it does less good of a job. Some called normal BMI folk are over fat and some overweight by BMI folk are athletic with low body fat.
It’s a great tool for following population trends.
I find the BMI percentile growth charts very useful in pediatrics, as both height and weight are changing. (You really can see a fossil record of pandemic restrictions in the charts!) And it is pretty easy to tell the difference between the kid whose BMI is up because she has taken up gymnastics or he is strength training for football versus the kid who is just getting fatter. BMI percentile increase is a screening flag, not anything diagnostic.
Of course the habits of exercise and nutrition matter more than the number.
Really? Here’s a place to start
The important thing to remember is the difference between “risk factor” and “destiny.”
So what? Just because that’s when the measure was invented doesn’t mean we’re still using their conclusions. It’s a simple physical ratio to take into account that height and weight are not independent.
Again: people don’t understand predictive, correlation, and risk factor.
Yes, exactly, when you’re visiting your MD. This is not feasible when conducting a study on thousands of people.
So, when the diet industry got them to change the BMI to show a 29 million Americans were suddenly obese- that was valid?
That is Health Risks of Overweight & Obesity, They do not mention BMI.
Yeah, we arent - the Diet industry made them change the numbers so suddenly 29 Million Americans were overweight or now obese.
Which is meaningless at an individual level. Which level is what we are interested in, no? Am I healthy? And for that BMI is nearly useless. Get a physical, with BP , bloodwork, etc. That will tell you how healthy you really are, not some numbers gleaned hundreds of years ago from malnourished peasants.
That never happened. In the context of BMI the words “obese” and “overweight” have precise meanings. It is accurate that the change in definition … expanded … the “overweight” category. It did not touch the “obese” group.
Completely agree that the “overweight” designation is not very useful and contains many who are at their healthiest possible lean and fat mass ratio, not all over fat.
In 1998, the National Institutes of Health lowered the overweight threshold from 27.8 to 25—branding roughly 29 million Americans as fat overnight—to match international guidelines. But critics noted that those guidelines were drafted in part by the International Obesity Task Force, whose two principal funders were companies making weight loss drugs. In his recent book Fat Politics: The Real Story Behind America’s Obesity Epidemic, political scientist Eric Oliver reports that the chairman of the NIH committee that made the decision, Columbia University professor of medicine Xavier Pi-Sunyer, was consulting for several diet drug manufacturers and Weight Watchers International.
From my cite. Yes indeed, it happened.
The “overweight” threshold. Not the “obese” threshold. They did not
THAT never happened. Then and now someone “obese” by BMI is highly likely over fat. “Overweight” is often fine, but sometimes over fat. “Normal” is sometimes over fat too.
I work in IT for a health insurance adjacent employer. I don’t want to say who I work for, because companies get cranky about that. However one of the tables of data we use is a list of diagnoses that doctors can use on claims, and BMI is definitely in there.
Negative level attacks can affect anyone. Let’s not undersell the dangers of energy drain.
(sorry, I couldn’t resist)
From research on the subject, it appears that only about 15% of people will compromise their own work, to corruptly aid a false result.
Saying that someone has a tertiary financial incentive doesn’t actually mean that the result is dishonest or unreliable.
Likewise, assuming that Weight Watchers had a corrupt intent is also a bit of an assumption. They may view themselves as a company out to improve the life of millions and that they’d be happy to go out of business because we all got fit and healthy.
Assuming that a chairman can force his preference on the rest of the committee is an assumption that, similarly, does not hold.
In terms of argumentation, these are largely just handwaves that allow a person to write a splashy headline that gets people to buy books and buy newspapers.
To be sure, you can have situations in the world like where a group of wine manufacturers get together, hold a wine contest, and dole out an award to each company that funded the competition, so they can all slap an “award winning” emblem on the label. There are 100%, unquestionable bits of nonsense that have been undertaken by corporations to mislead the masses, for profit.
But likewise, you have the evil corporation of a Mr. Oskar Schindler who bribed and lobbied government officials to save lives, and Nikola Tesla who gave everything away to improve the quality of life of everyone on the planet.
A company that makes sanitization equipment would have a motive to push for regulations that ensure our food pipeline is sanitary and safe for consumers. If they found some doctor who had done research and calculated a number of saved lives if such a policy was put in place, and offered to pay for his tickets to go to DC, have they just wreaked evil on the American people?
A splashy headline and a good conspiracy story is not evidence for or against anything. You really have to investigate the specifics and question the simple solutions that people will try to hand you. Maybe Mr. Oliver makes a convincing case for corruption, if you read his whole book. My guess would be, however, that it really is as simple as that most of the medical community thought it made more sense to line up with the rest of the world, and Weight Watchers’ primary impact was to provide the monetary banking to fund pushing through the naysayers that hate change. Maybe their intention was selfish - maybe not - but that doesn’t mean that they were on the wrong side of the issue.
Insurance works the same as sports betting. Your financial success rides largely on your ability to predict the future more accurately than the other guy.
An insurance company doesn’t want to drop a customer who is large and muscular. That person is of no risk to them and, likely, will cost them less than their average customer. They have a financial incentive to differentiate between overweight and muscular.
If they had something that was more accurate and reasonable to calculate than the BMI, they’d be dumb to not move to it. And to the extent that they don’t, I’d expect that it’s either because it’s not yet reasonable (e.g. almost no one knows their BRI) or they simply haven’t been able to move to it yet, due to inertia.
As a dedicated weightlifter, my BMI is higher than the waist size of my favourite jeans.
But like many statistics it is meant to apply to populations, not individuals. It is a useful but imperfect tool. Cheap and easy to do, simple to understand, moderate to high correlation with outcomes. Not meant to be definitive.
Everyone understands it does not apply to everyone, imposes arbitrary categories, and has significant false positives and false negatives. This does not make alternatives better, though some might be. I thought the list of reasons was fairly weak. Not useless, just sometimes misused.
As it should be. Not sure how adult side uses the diagnosis but obesity is often relevant to other problems a person has and should be listed as a diagnosis on the problem list. Again, “obesity” by BMI definition is highly probably (even then not always) associated with negative health impacts, and of course grades 2 and 3 obesity more so.
I can’t imagine too many (any?) using “overweight” as a diagnosis though.
Just to nitpick, Adolphe Quetelet published the treatise that included BMI in 1835, and his population looks to be from Belgium. They may have been peasants in the sense that they were not aristocracy, but not necessarily the starving lower classes this term brings to mind.
Especially because he was trying to determine l’homme moyen (“the average man”)
It fails for the reasons echoreply mentioned. There’s a calculator here:
You need to know your waist and hip measurements. Almost no one knows this off the top of their heads. And people are likely to get them wrong if they measure themselves.
The formula is also more complicated than BMI, but I guess we can depend on online calculators for that.
I’m thinking becoming a tool for when I go to my doctor. Actually you just need height and waist: It’s
364.2 − 365.5 × √(1 − [waist circumference in centimeters / 2π]2 / [0.5 × height in centimeters]2)
And yes online calculators are available for free. People do need to know where and how to measure waist though.
Realistically, BMI and BRI only have three purposes:
- To provide guidance on the value of different medical guidance / lawmaking related to diet, fitness, and bodyweight.
- To allow a doctor to have a sense of a person, from a piece of paper, and to be able to relate changes in condition to likely causes.
- To provide a numeric reference for the ignorant and deluded.
The most valuable use for the statistic, standing alone, is the first. For that, it’s wonderful.
For the second, it’s going to be fairly situational. But, generally, the doctor is going to hear about your medical complaint at the same time that they physically see you so the precise number probably isn’t too relevant. They could just have some nurse write down, boney/normal/overweight/obese simply by looking at the physical human in front of them, without any measuring at all and, in general, that would be sufficient for tracking purposes and sufficient as a method - arguably better.
And, for the third, having an official number and official ranges can allow someone who grew up in a vacuum to be able to learn how to label people. It can (in theory) help someone with body dysmorphia to fight the image that they’re seeing in their head and try to relabel things correctly (though, my understanding is that this doesn’t usually work in practice and, instead, cranks up the obsession/stress level).
For the second use-case, the purpose of the BMI isn’t so much for medical purposes so much as it is to calibrate your own senses via route 3. Once you’ve done that, and your staff has done that, BMI is worse than what you can see with your eyes and so would be BRI.