The last time the Standard BMI was officially updated through proper, official channels was in 1998 (1, 2, 3). At that time, the NIH changed the threshold for “overweight”, officially lowering it to a BMI of 25 and aligning it with World Health Organization guidelines. The only thing the Standard BMI does, via height and weight, is estimate body fat to assess health risks.
That is literally the only thing the BMI does, estimate body fat to assess health risks (4, 5, 1, 3). It does nothing else (no, it does not estimate health, only healthy weight). Yes, the accuracy of the BMI is debatable, for sure. However, the simple definition of the Standard BMI is not debatable — it is set in stone until changed via official protocol.
This is the current official Standard BMI scale:
18.49 or less – underweight, not a healthy weight due to too little regular white/yellow body fat (common adipose tissue)
18.5 to 24.99 – normal weight, healthy weight due to no excess regular white/yellow body fat (common adipose tissue)
25 to 29.99 – overweight, not a healthy weight due to too much/excess regular white/yellow body fat (common adipose tissue)
30+ – obese, not a healthy weight due to way too much/excess regular white/yellow body fat (common adipose tissue)
In 2016, the NIH released its first-ever (initial) definition for normal-weight obesity (skinny fat)(6):
“Normal-weight obesity syndrome is characterized by excess body fat in individuals with adequate body mass index (18.5-24.9 kg/m(2))”
Which directly contradicts the Standard BMI definition (1, 2, 3, 4, 5). No official change to the BMI happened – the BMI definition/scale did not change.
18 Comments
Septimaeus@infosec.pub · 6 pts · 8d
IIRC the prominence of BMI in general health profiling has persisted mainly due to the historic practical difficulty of assessing BF% where clinically consistent results can depend heavily on technique and methods used, few of which are less invasive than having a patient simply step on a scale.
But at this point we have so many additional nearly touch-free methods aided by technologies like bioimpedance and infrared imaging that I suspect the greater factor describing the persistence of BMI-based metrics must be just how deep the existing integration is between clinical and actuarial health assessment.
If that is the case, I imagine the improvement requires either (A) a responsible and active standards-setting organization like a (competently-administered) DoH to finally push through an update to standards (bureaucratically) or, more likely, (B) switching to a single-payer system where stronger incentive is material at a high enough level to adopt superior system-wide guidelines and practices.
Edit: to be clear, I’m definitely not arguing for BMI. It is obviously an inferior proxy.
fellowoneresearch@sh.itjust.works · -7 pts · 8d
If you had actually read the science, you would understand that we are not arguing for BMI. it is very limited. So your comment proves you do not understand.
Lean body mass (LBM) -- DEXA, InBody, etc. -- is a composite of all non-fat body tissue. it is not a direct measure of muscle tissue. Like BMI, LBM is an inaccurate proxy estimate at best.
As of September 13, 2026 --
Please actually read the science before you make unfounded assumptions.
Septimaeus@infosec.pub · 2 pts · 8d
Um, I don’t know how what I wrote came across as pro-BMI. I was arguing that we’re past-due a change, and only theorized what that change might require at an institutional/infrastructural level.
fellowoneresearch@sh.itjust.works · -7 pts · 8d
That is exactly what our science is working on doing. We are developing new direct standardized ways to measure muscle/body composition along with an actual standardized baseline phenotype -- to evolve beyond antiquated proxies and no standardized baseline phenotype.
Septimaeus@infosec.pub · 2 pts · 8d
Excellent! This is needed work in an important area. Thank you for your contributions.
The_v@lemmy.world · 1 pts · 8d
For a quick and fast way to estimate obesity an easier method has been around for years now - Waist-to-height ratio. This ratio capture all of the skinny/fat issues that the BMI scale misses. It also more accurately avoids the higher muscle mass mis-calculations that the BMI scale is known for.
https://en.wikipedia.org/wiki/Waist-to-height_ratio
The entire BMI scale is being tossed out and replaced with the waist-to-height ratio. That you even mention it is bizarre . The science on the subject is pretty settled at this point. As a quick and dirty estimate of health relative healthy weight, it's extremely easy and more accurate. It also works with all ages over 5 years old and all ethnicities.
For example at 240 lbs at 6'3" my BMI is 30.6 (obese). My waist is 36" however so my Waist-to-height ratio is 0.48 (Healthy).
fellowoneresearch@sh.itjust.works · -4 pts · 8d
No, it does not. Waist-to-height ratio does not measure muscle in any capacity. You have no idea how much muscle you were born with or without (skinny fat). You have no idea how your muscle compares to the average, because there is no baseline average to compare it to. You have no idea if your body falls within "normal" phenotype range, because there is no standardized baseline phenotype to compare it to. The next time you see your doctor, ask them how much muscle you were born with, how it compares to the average, and how it compares to the average phenotype...let us all know what they say...
Yes, BMI is a limited, inaccurate proxy measure. But it is the only currently NIH-accepted method, and has not been officially changed by the NIH since 1998.
Lean body mass (LBM) – DEXA, InBody, etc. – is a composite of all non-fat body tissue. it is also not a direct measure of muscle tissue. Like BMI and waist-to-height ratio, LBM is an inaccurate proxy estimate at best.
As of September 13, 2026 –
adespoton@lemmy.ca · 1 pts · 8d
I wish more people would realize that waist to height only really works for people with a tendency towards BMI-style obesity.
I have virtually no white/yellow fat. My scale says my body is 4.5% fat. I have lean muscle and do endurance training. But I can tell when my muscle is deteriorating because my joints become too loose, and when I get too much interior fat because it presses on my intestines and kidneys. Scale and waist to height both say I’m an Olympic level athlete level of fit… but I’m just slightly above average fit with unusual genetics. I still have to watch my cholesterol, still have to watch my heart, and I know that if I stop exercising for a few weeks, it will severely impact my health without being outwardly very visible.
Hopefully we can find some diagnostics for useful health baselines and tracking for all this. Right now, listening to my body is the most quantitative solution I’ve found.
DrBob@lemmy.ca · 4 pts · 8d
What are we supposed to do with this information?
fellowoneresearch@sh.itjust.works · -8 pts · 8d
Like any new science, ask a question to clarify and understand.
DrBob@lemmy.ca · 2 pts · 8d
Your bio says you've been researching the issue for 23 years, and I'm supposed to ask a question to demonstrate relevance?
Just for the record, the first place I recall reading about "skinnyfat" was in Microserfs by Douglas Coupland. It was published in 1995 so the term was bouncing around before that for Coupland to have picked it up.
adespoton@lemmy.ca · 1 pts · 8d
I was a subject in a study on it in 1997. I never did see the published results; I suspect they never got enough people to make it a legitimate study. Seems like not much has changed since; it’s still a collection of hypotheses without enough data to say anything useful.
fellowoneresearch@sh.itjust.works · -4 pts · 8d
In terms of official literature, it was not first mentioned until 2006 - "thin outside, fat inside" (TOFI).
You ask questions to clarify things.
DrBob@lemmy.ca · 1 pts · 8d
In terms of peer reviewed literature I can only find the term twice from a quick skim of PubMed. Both times it's in quotes referring to bro science. Do you have an actual lab?
eta: read your website. You are somewhere between crackpot and grifter. Blocked.
fellowoneresearch@sh.itjust.works · -4 pts · 8d
2006 - TOFI, 2016, normal-weight obesity.
Every article in the white paper is thoroughly referenced.
These are the current facts:
No one has been asked for anything.
fellowoneresearch@sh.itjust.works · -5 pts · 8d
PS: Seems like a "Recovering academic" would have more respect for independent research.
beliquititious@lemmy.blahaj.zone · 1 pts · 8d
Forgive my ignorance, but I'm curious about your bibliography and research methods. I wanted to learn more about the issue but was surprised to find a new york times article, a Wikipedia page, and a substantial amount of sources there were your other articles. It's my understanding that it's bad form to cite yourself, especially if your own work is the majority of the bibliography? Only a couple of the sources cited seem to be actual published research. Is that normal for this kind of piece?
fellowoneresearch@sh.itjust.works · -4 pts · 8d
Getting cutting-edge science out to the world is very difficult. We are working on a dataset peer-reviewed paper, as well as a MRI Study (you can find on ResearchHub).
As scientists, we prefer to maintain privacy as much as possible, especially on social media where ruthless ire, hatred, derision, and bullying are common. All of our work can be reviewed at the links in the bio. Or feel free to ask any questions here.