BMI is correct for about 80% of people. The biggest problem is for people that are very tall, as you are 2 standard deviations from average height it works less well. The muscular argument is a fairly weak one, as the extra weight even as muscle can still be bad for your skeleton (and many that say they are muscular aren’t 2+ standard deviations from average).

I’m slightly shorter than you, but the best I ever felt was when my BMI was on the edge of normal and overweight.

Are you visibly fat? If so, it works. The only time it doesn’t is when you are visibly ripped.

BMI works for me, skill issue :P

It’s a screening number. It’s not supposed to be “trustworthy” because it doesn’t mean anything other than as an arbitrary point for grouping individuals into categories that can be used to estimate risks and make generalized decisions.

As a thought experiment, consider another commonly used screening number, that breast cancer screening should become routine at age 40. Does that mean breast cancer doesn’t happen to women below age 40? Of course not. Does it mean breast cancer will always happen eventually above age 40? Also of course not. What does it mean? Basically nothing. There is nothing magic or medically significant about being 40 years old specifically. It’s just that we decide that’s a good approximation of the time when the benefits start to outweigh the costs for most people.

For an individual it’s a pointless number that is completely erased by a massive number of individual risk factors and situational factors. You are an individual. It does not apply to you.

For large populations, it’s a decent generalization. For people working with large populations, it can be a very useful measurement. But it’s not really supported to be anything more than that, and it’s not particularly useful to apply to you individually. We do of course frequently apply it individually, including many doctors (usually following the direction of insurance companies who DO care about large populations and DON’T care about you as an individual), but that’s not really particularly justifiable, that’s just a reflection of how our health care system works (or doesn’t).

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The BMI was created by a social scientist to place people into rough categories for a study on how obesity impacts social interactions, in greater research on how the “average man” represented a social ideal. The fact that we now use it to define who is obese and overweight is a little insane. While it’s been adopted by major health organizations (and hopefully adjusted by genuine health professionals), it is a horrible singular indicator of physical health. People in the extremes are statistically more likely to face health issues. This is not the same thing as “being in the obese category makes you unhealthy because you are fat.”

Afaik it’s quite reliable as long as you’re not very muscular. I’m 190cm and roughly 80-85kg, which is a quite normal (but a bit higher than avg) according to BMI. I also have a bit of a beer belly and definitely feel like I could lose some fat.

Unless you work out a lot and are muscular, I’d expect the classification of obese to be correct for your height and weight. 10cm taller than me and 35kg heavier doesn’t sound like a weight within the healthy range unless it’s muscle.

Obese is just a medical term. BMI is a height to weight ratio so it’s accurate in that way. It does miss as a measure of over-fat vs. overweight, but more often in the other direction (fat people with normal BMI) but it can err in the other direction sometimes, sure.

The easiest and most accurate way to tell if you are over-fat is waist to height ratio. Your waist circumference should be less than half your height. So if you are 198cm, waist needs to be less than 99cm. This is the only stat that’s been a reliable predictor for health problems from too much fat (because it’s the torso fat that’s more problematic health-wise)

The other thing to remember is that the risk curve for underweight is steep but for overweight it’s shallow - a couple extra kg has almost no extra health risk.

To have a “normal” BMI my brother would need to lose all the fat he has, and chop off his leg. In a general case it’s okay-ish. In specific circumstances it’s totally rubbish.

It’s statistically correct, but not specifically correct. It doesn’t tell you for certain that you, personally, have too much body fat (or too little fat/muscle), but it’s a good indicator.

And that’s really what you’re looking at; you’re trying to figure out if you have more body fat than you should.

Harpendens skin fold calipers–when used by a trained professional–will give you a more accurate measure of your overall body fat percentage. And InBody scale will measure bioelectrical impedance (essentially running a low-voltage current through you and measuring impedance) to give you a fairly accurate measure of your body fat percentage, but how well hydrated you are can significantly affect the reading. Hydrostatic underwater weighing was long been the gold standard for measuring body composition. BUT dual x-ray absorbiometry (DEXA) has overtaken it, because it’s significantly easier on the person being tested.

That said, body fat alone doesn’t tell you if you are actually healthy. You can be fairly low in body fat, and have horrific cardiovascular fitness. And being exceptionally heavily muscled, (say, 200kg, at 7% body fat; Mr. Olympia levels of muscle) doesn’t appear to be healthy on your joints and heart either in the long term.

It’s tricky,

It works well at a population level, and the reality is that most people with a BMI indicating that they’re overweight are actually overweight

It doesn’t account for muscle, bone density etc.

I have visible abs, but my BMI is overweight. It’s because my bone density is unusual. I sink in water, and I have muscle

I also am middle-aged and have some fat that I didn’t used to have

People like to write BMI off because it tells them something they don’t want to hear. Everyone refers to athletes and the like, and I’ve upset plenty of people by saying “so, you’re a professional rugby player, are ya?”

It’s not perfect by any stretch, but it may give you something to consider

I have had people describe me as “skinny”, when I’m definitely not. Especially Americans

Most people are so used to seeing fatties that a healthy person looks thin by comparison

Its flawed but a decent screener. Follow up with a blood test if you are concerned. BMI doesn’t distinguish between muscle/fat and some people can have a high BMI but be metabolically perfectly healthy-others not so much. Its a very wide spectrum that needs to be looked at on a case-by-case basis. Also fat tissue (adipose) is involved in much more than just energy storage, its quite active in inflammation, metabolism and disease processes. Source: I did my MSc on obesity and gut health. Bonus fun fact: theres no standard definition of “high fat diet”, many meta analyses are comparing wildly different diets to draw some pretty “interesting” conclusions!

It’s usefulness is in it’s simplicity, not in the accuracy or precision at an individual level.

Especially if you like lifting weights you can get some wild errors.

the BMI was developed by a European data nerd who only measured white working class men from one country. it does not really account for deviations from that specific type of person, like gender, ethnicity, or musculature. all it can say is how your weight relates to your height, and the medical field has a real problem with treating patients like human beings, let alone accurately identifying someone’s needs. so, uh, i wouldnt stress over your BMI

BMI is kinda like IQ, certainly useful, but it doesn’t tell the full story.

If it is high, you may be fat, if it is really low, you are definitely underweight.