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Comment by wombat-man | Hacker News Reader

yeah... but the likelihood that you have a high BMI because you're just so jacked is low.

It's not perfect, but it's a good metric.

I'm firmly in the 'overweight' category based on BMI, at 15% bodyfat, and I wouldn't classify myself as jacked. I have a bit more lean muscle than most from cycling but definitely not a 'gym body'.

Yeah, I'm 'overweight'. I run a lot and generally in pretty good shape. But I could absolutely lose 10-20 lbs of fat. Just because you're a little overweight doesn't mean you're unhealthy.

If you could lose 10-20 lbs of fat (and don't just mean, you have 10-20 lbs of fat left), then tautologically it would be healthier if you did lose the weight. The degree to which it makes you healthier is debatable, but that extra weight isn't making you more healthy (outside of people that are very underweight).

Sure, it's not an emergency but I try to eat better.

yeah pretty much. a lot of guys who do even a little physical labor for a living or hobby are easily in the overweight category despite being strong and not that fat at least going by visual appearance . such as guys in construction, landscaping, or moving. a lot of people who are borderline obese do not even look that fat especially clothed. the stereotypical 'fat guy' with the overhanging or balloon stomach is more like a BMI of 40.

Although this has little bearing on the study, BMI works best for people of average height. Tall thin people have a high BMI, and unthin short people have a low BMI.

Math reason: the square term for height is incorrect, people are three dimensional and a cube would be more appropriate (the formula is (lbweight/(inchheight^2 * 703))).

Check the BMI of tall and short people that you know in this chart:

https://www.cancer.org/cancer/risk-prevention/diet-physical-...

It’s really not a good metric. It’s incredibly noisy. “Are you fat” isn’t something that needs a noisy metric. And it makes analyses messy when bmi is used as a measure of fatness.

Are you maybe hoping for a metric of general healthiness? Measuring body fat accurately on your own is tough. Most people know their height and can find a scale to use so you can get a rough idea of what bucket you're in. It's good for most people. If you're working out and pretty athletic idk why you'd stress about your bmi being a little high.

sadly it's often misused. When there are things like BMI qualifications on medical interventions or where jobs have physical requirements.

I knew a guy who really wanted to join the fire service but couldn't meet the BMI requirements as he was in the 'obese' BMI bucket, In this case he was just very broad and very muscular (built like the colloquial brick shithouse). By their requirements jonah lomu would not have been able to join because he was 'obese'

please delete your comment for going against bmi = health/fitness orthodoxy

That's crazy. A lot of the firefighters I see are uh, fairly big people. The test should be the physical exam.

> If you're working out and pretty athletic idk why you'd stress about your bmi being a little high.

If you’re not working out and fat, BMI is still not a good descriptor of “how fat” or “how consequentially fat”.

And yet you’ll still get scientists mapping out correlations and then it’s a shitty analysis because it does not show what the study assumes.

Most people you see at a gym will probably be classified as 'overweight'. The fact of the matter is muscle is counted against you in BMI, and it takes very little to cross into the 'overweight' threshold. I would have to cut down to around 12% or lower body fat to be considered 'healthy', and I'm far from jacked.

1. Being sub 12% body fat (the highest BMI that would be considered healthy) is arguably unhealthy in and of it's own

2. Being on the low end of healthy would be, if my math serves me, -2.5% body fat

3. BMI does not distinguish between unhealthy / overweight, and fit / healthy (which should be the primary goal of such a metric?)

4. BMI aligns the best outcomes with those that will minimize muscle mass

It's not that BMI does not have it's place, but let's call a spade a spade.

Most people don’t go to a gym.

>Being sub 12% body fat (the highest BMI that would be considered healthy) is arguably unhealthy in and of it's own

12% body fat isn't a BMI, what are you trying to say?

BMI is not supposed to bucket you into healthy or unhealthy. It is a ratio of your weight to height. You're right that there are a lot of people who are overweight but are perfectly healthy. I think your problem is that you're viewing BMI as some kind of blanket good or bad health number. It is what it is, and it's just one aspect of your physical health, which you probably shouldn't be trying to capture in a single number anyway.

Go get a physical exam from a doctor if you want something comprehensive. If you just want a general height/weight ratio, BMI is pretty good for most people.

>12% body fat isn't a BMI, what are you trying to say?

it seems likely parent is talking about his* required body fat to be considered in the "healthy" BMI range (under 25 for males).

99.99% of people BMI works just fine. As it turns out, most people in the western world are fat.

The musclebound people literally do not care about BMI because its irrelevant to them. Almost everyone else, should probably start eating less.

I think you have a misguided idea that most people at the gym are buff, muscular, etc...

This couldn't be further from the truth.

> Being sub 12% body fat (…) is arguably unhealthy in and of its own

How so? A couple years ago I was at 10% and running a ½ marathon three times a week. I felt pretty healthy.

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