I was considered obese by BMI standards in high school, when I was outside with friends riding bikes all day and phys ed at school where I lifted weights daily. I would be impossibly thin if I tried to achieve it now.
It's only a rough guideline. There's Olympic athletes that would be considered overweight based on their BMI that are basically all muscle. It's a decent guideline for your average person, but there's outliers that don't fit in that scale. After all, you're making a judgment based on just 2 parameters.
So it's a decent guideline like you said, barring some extreme exceptions like olympic-level athletes which aren't a high percentage of the population.
My workout partner in college was clinically obese based on his BMI. He was like 6% body fat and had more than average muscle mass but was not huge. He was built like Hugh Jackman as Wolverine except shorter. There's lots of guys like that. Not sure I'd consider them to be extreme exceptions.
Nah, its off in a lot more ways. Bone density, it exaggerates tall peoples "fat"ness, and short peoples "thin"ness, racial differences, differences between the sexes, so on and so forth.
Its a 200 year old formula that's extremely generic. There are newer ones that are better, like waist to height ratio, hip and height, body comp, etc. Each one of those has some flaws too, but the waist to height is apparently pretty damn accurate. Way more than BMI. But it doesn't work for certain ethnicities, children, or people with medical conditions that would enlarge their waist.
Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health. A body mass index (BMI) over 25 is considered overweight, and over 30 is obese (From the WHO)
Obesity is quantified using BMI by medical organizations because there isn't an effective way to quantify it otherwise, but it's in the same way as using IQ is a shorthand for intelligence or the DSM is used to describe mental illness. It needs a qualified professional to use the raw data point in combination with other factors in order to tell you if your body fat is actually unhealthy.
High body mass does also add its own strain independent of fat, but the actual intent of the term obesity is about whether you have a level of excess fat that lowers health outcomes, not size by itself. (It also wasn't actually ever intended by it's creator as a measure of health, just as the broad stroke data point it is.)
But the alternative to being high weight without high body fat % is high muscle mass, which is only a thing in a few humans.
IQ is indeed not representative of intelligence because we can't represent a lot of functions of intelligence in a sensible test.
The DSM is a list of diagnostic criteria. Hopefully patient-facing shrinks don't use "raw data" outside of said diagnostic criteria to make judgements on diagnoses, otherwise they're just using arbitrary non-spec information.
What other raw data is used in the weight example?
It's a thing in a good number of humans. Once you do pretty much any strength training (or just heavy lifting) at all, BMI loses its value pretty quickly. It's a rough indicator.
The DSM is definitely not intended to be stand alone. It is a set of general guidelines and definitions to inform the evaluation of a mental health professional. Most people check a good number of boxes on a good number of those checklists. The checklists are a tool to be used in collaboration with the professional judgement of the doctor. Almost every individual checkbox is "checked" or not based on the doctor's subjective evaluation.
Muscle mass and general body composition are part of it. Some people are naturally bigger and healthier at more weight than others. Some are naturally smaller and healthier at levels that would be unhealthy skinny for others. Presence of other obesity related illnesses are another. If you're showing signs of heart disease, breathing issues, etc, in addition to being big, that's a sign that losing weight will improve your health outcomes. BMI is a very rough yardstick that is used for the purpose of evaluating populations over time. It is not a good way to look at the health of a single individual without context.
Once you do pretty much any strength training (or just heavy lifting) at all, BMI loses its value pretty quickly. It's a rough indicator.
So it seems like there's just an exception in the few gymrat type folks out there and athletes. Still seems like a small exception group compared to the general population. That aside, the bit about certain people being healthier while bigger/smaller seems anecdotal and unscientific afaik.
Most people check a good number of boxes on a good number of those checklists.
I don't think most people would check many boxes for schizophrenia or gender dysphoria or even ADHD, though as always the real test is whether the meds help.
As for GAD or something more unspecific it's really more about whether it impacts their life negatively or not which is a presumption under which those checklists are meant to be taken.
Still, I've never heard of someone checking off all the boxes while self-diagnosing and then going on to not be legitimately diagnosed outside of a few cases where supposed professionals usually apply some discrimination based on immutable characteristics.
Almost every individual checkbox is "checked" or not based on the doctor's subjective evaluation.
Yeah this kind of just demonstrates that the doctor's part of the equation is utter bullshit
"Gym rats" means anyone who's ever played a sport. Or done a job with manual labor. Or did any of many other things. BMI is "unscientific as fuck". It was literally never intended to be used anything like how it's used. It was solely intended to give a broad strokes single number for size relative to height (in a very limited initial population). There is no actual basis for its use anywhere.
The entire DSM was designed for the sole purpose of being used by a doctor. It was never intended to be used to self diagnose, or in literally any context outside of being used by a professional. The doctor's part of the equation is the whole point and the only thing that makes the DSM useful in any way. It is not standalone. It is a tool to enable doctors to have a consistent framework and process to do their job.
It is strongly correlated. High IQ reliably predicts high performance in a variety of cognitive tasks (even ones not covered by the IQ test).
To pretend that IQ is a sham is dangerous, because that would suggests that definite proof to the contrary makes the fascists right. Which it doesn't.
Firstly because statistical correlation is useless for individual outliers (e.g. high BMI Olympic athletes). It says something about a population, but can only suggest something about an individual (high BMI can mean someone is overweight, but further analysis is required to make a diagnosis).
Secondly and more importantly because using synthetic metrics as a proxy for the value of a human life is an abhorrent practice that has only ever led to misuse and dangerous if not catastrophic or outright genocidal policies. I don't mind IQ tests as an indicator for psychiatric diagnoses, or for aggregate research on human cognition. But if, for any reason, someone's IQ needs to be made public or handed over to an institution, then we're on the road straight to fascism.
It's correlated to a very narrow subset of skills that are a small part of intelligence. It's a predictor of successful outcomes in the broad sense, but considering the strong correlation to access to education and other similar environmental prerequisites to healthy development, claiming there's a particularly strong causal relationship between IQ and success is relatively bold.
My whole assertion is that using IQ as a value measurement is fundamentally not very useful. In the specific case of race (or cultural background, or whatever), there's no functional way to control for the confounding factors, so you can't really draw any conclusions about the "merit" of the relevant population at all, even if IQ did that.
Like I said IQ should never, ever be used as an entry exam or any other kind of social determinant. Not least because of the racist/classist history. However, it does have a signification and legitimate uses, and to pretend otherwise is scientific negationism. We do not have to listen to racist conspiracy theories about why some populations have a lower IQ than "us", when we have known and repeatedly demonstrated for many decades that differences in IQ at the population level is entirely predictable by education and health (the Flynn Effect). That's it, that's the necessary and sufficient counter-argument to the racist arguments you're referring to.
Put another way, education does not just make people educated; it makes them more intelligent. Someone who has gone through standard schooling is empirically proven to be statistically better at novel abstract thinking than someone who never went to school. Which is kind of obvious when put like that, but you can't prove or study that phenomenon scientifically without the use of tools like the IQ test.
Poor african countries have a lower IQ than the world average, and that is an irrefutable fact. Does that mean:
a) Life outcomes are not shaped in anyway by socioeconomic background, therefore [insert racist theory here]
b) I refuse to look into the possible causes and therefore IQ tests are racist
c) We can infer that poor populations would benefit from increased financing of childcare and education, it's a winning move for literally everyone.
The topic of IQ tests is really uncomfortable because it unearths the really uncomfortable fact that socioeconomic and geopolitical factors have not given us all an equal shot at life, even down to how intelligent we are likely to become as adults. It challenges the myth that anyone can just pull themselves up by the bootstraps, work at mcdonald's, and become a triple harvard graduate. But it's not neuroscience's fault that the world is unfair.
Controlling for confounding factors is, like, half the point.
Racists will tell you [x country] is lower IQ than [y developed country]. Which is probably true. What they won't say is that that average IQ is probably the same as [y developed country 100-200 years ago]. IQ being affected by education is the whole fucking point; widespread access to a good and long education provably leads to a more intelligent population, which we have seen time and time again with industrializing countries (including in the West since the IQ test is old enough that we can see the average IQ rising since the industrial revolution).
And when the scores rise, they're adjusted to the mean. Because 100 means of average intelligence, and the average intelligence rises, so the average is adjusted for.
Ulric Neisser estimated that using the IQ values of 1997, the average IQ of the United States in 1932, according to the first Stanford–Binet Intelligence Scales standardization sample, was 80. Neisser states that "Hardly any of them would have scored 'very superior', but nearly one-quarter would have appeared to be 'deficient.'" He also wrote that "Test scores are certainly going up all over the world, but whether intelligence itself has risen remains controversial."
Can you please give a definition of intelligence that does not correlate with IQ? Because scientists have been trying, and as far as I know, failing.
Or I guess we can keep pretending that intelligence is fully inquantifiable and therefore we won't be able to quantify how socioeconomic background affect people's wellbeing. I guess that does have the upside that we don't have to face the hard truths of our world, that unequal access to healthcare and education does affect people's cognitive abilities and that the worse life outcomes of poor people being self-inflicted is a myth perpetuated by the ruling class to justify their continued oppression. No, it must be the IQ tests that are racist.
"Sex, Lies, and Brain Scans" talks about IQ and the problems with IQ. There's also "Delusions of Gender" by Cordelia Fine, and "Neurolinguistics and Linguistic Aphasia."
First, I have had a neuropsych evaluation done and an IQ test. It has areas that are subjective and open to interpretation by the test administrator, already making IQ tests suspect. There is no way to quantify intelligence using actually measurable data. Sound is measured in Hz, light in nanometers, and these things fit nicely on a scale with numbers. Intelligence doesn't require something so discrete. Octopuses, parrots, elephants, all have different brain anatomy from us and each other and are all quite intelligent. It's hard to say what the secret sauce even is, let alone measure it quantifiably.
Many neuropsych tests aren't actually able to prove anything substantial about the brain itself or a person's abilities, short of serious cognitive tests like the clock test which is also fallible. The reason for this is that most human intelligence is pretty close to each other and it's actually hard to find substantial, consistent differences in the population. Think of how close in intelligence a bear is to a human - trash can design at Yellowstone is famously difficult because bear and human intelligence overlap so much. Humans are much more alike cognitively with each other than a bear.
Second, we have the issue of implicit bias and priming. That tells certain groups if they are allowed to be "good" at something, if something is "meant" for them, if they will do well at it. When controlled for cognitive bias, IQ levels across most groups are equal and IQ tends to start to measure persistence/"resiliency" between the groups - which can be affected by something as simple as a coffee that morning or bad sleep.
Last, we have actual medical conditions that make it hard to communicate and pass an IQ test, but the person's IQ is intact/normal for them. There are musical geniuses that aren't picked up by IQ tests, as well as athletic geniuses (Wayne Gretsky), artistic geniuses, and social geniuses.
You're getting push back because people loathe the idea than an intrinsic value like IQ might define them. Same reason the bullies kicked my ass up until high school. They thought I had something they weren't born with, couldn't compete with, thought I had an unfair edge.
Sorry folks, IQ is a large component of who you are, and no, you can't control that number. OTOH, back to my childhood ass beatings, I wasn't much smarter than the other kids. 119 IQ, tested the same at 6 and 16-yo, "bright normal", nothing to write home about. I did well in school due to my parents drive and my love for knowledge. None of my friends took a diploma on graduation night and none had as low an IQ as I. Go figure.
IQ is a legitimate part of you, like it or not. Emotional quotient is as well. I know damned well that my IQ is far higher than my wife's, and her EQ is stunning compared to mine, makes a nice balance. But does that mean I'm smarter than her? I would argue it does not. People called my last boss a "dumbass", but only because his IQ outstripped his EQ.
tl;dr: IQ scores are important and defining, but there is much more to get the gestalt of a human being.