There are a bunch of other, sillier possible co-founders as well. Is low BMI associated with bicycle use? Probably. Is bicycle use associated with getting hit by a car? Also probably. How about swimming and drowning? Or extreme running and heart attacks? A bunch of possibilities of this nature.
Are fat people more resilient to gunshot wounds? Stabbings?
Obesity and Anterior Abdominal Gunshot Wounds: A Cushion Effect - PMC.
Obesity May Not be Protective in Abdominal Stab Wounds - PMC.
Impact of body mass index on injury in abdominal stab wounds: implications for management - PubMed.
Yes it is the problem with associations. They are correlations, not necessarily causations. But for what it’s worth “Compared with BMI, BRI had narrower CIs and higher sensitivity in estimating risk for all-cause mortality” (from that article).
I’ll still bet on it also being in and of itself a limited tool. Just maybe a better one than BMI alone. Someone with a lower BRI should have the risk of frailty investigated, but it may not apply. A higher BRI should definitely be evaluated in depth for possible opportunities to improve on nutrition and exercise habits. So on. In that regard not much different than BMI.
FWIW it fits well with my preferred measure: the scale means little to me; I follow my belt hole. I’ve gained close to ten pounds back since Spring peak marathon miles and switching back to more strength training and cycling. But my belt hole is the same. I am sure some is fat but as long as the belt hole is comfortably the same I am happy.
No doubt, that all things being equal, 1000 very overweight people will die before 1000 average weight people. But we are not a point in a study. Each person needs to get a physical exam by a qualified MD, and that will tell you more things about your health and dangers to it, than some weird shit biased BMI number. If you are “obese” per BMI- you may or may not be healthy. The BMI cant tell you that, only a medical exam.
Right.
I have long been skeptical of BMI being applied to all shapes and sizes. I believe that the calculation was based on actual measurements, but that the sample only included people within a certain height range. As others have mentioned, it does not take into account the body type and makeup of the weight. It therefore assumes that beyond certain limits, the additional weight must be detrimental to health.
The classic example is Shaq (back during his playing days). His BMI puts him well into the “obese” range, yet no one would have considered him “unhealthy”.
I, on the other end of the spectrum, feel I am another example. At 5’1" 182 lbs, I am into the “obese” category (BMI like 34 or something). I was discussing this with my personal trainer, and he also agreed that I wasn’t necessarily “unhealthy”. So I decided to work it backward: how much weight would I need to lose to get to the “healthy” range. The answer: some 50 lbs ! Over 25% of my current weight. (In case you were wondering, I hike, backpack, rock climb. So I’m not just an immobile “blob”). Which then led to “where” to lose 50lbs from ? Cut off a leg ?
As pointed out, BMI, at best, should be used as an indicator to have additional tests/measures to determine overall health. Yet my doctor, when I present this information (with all other tests she’s had done don’t indicate any issues), still tells me my “BMI is too high” and that I need to lose weight. She agrees that 50 lbs is excessive, so that would kind of indicate that being merely “overweight” is healthy enough ? Just how far out of the “normal” range is still “not unhealthy” ?
Yes. And statistically at significantly increased risk for a variety of conditions. Yes, if regularly physical active and eating a healthy nutrition plan not necessarily unhealthy.
Short version is that an obese person who loses 10 to 15% of their body weight by way of lasting nutrition and exercise improvements captures most of the health benefits.
My guess is that you, as an active person, have a better score on BRI than BMI, and that the improvements from that 10 to 15% loss are in general much bigger on BRI than BMI, reflecting the tendency to lose visceral fat more with that weight loss.
Weight is sticky, and very few people actually do this.
Are there good studies of health benefits of losing weight? Not benefits of being less heavy, but of people who were X, became X*.9 due to diet and exercise, as compared to people who were X and remained at X?
I wouldn’t be surprised if the very first BMI paper, written 200 years ago, was limited in that way. I’d be real skeptical, though, that 200 years later and across hundreds of nations and hundreds of thousands of hospitals with databases of digitized medical records of billions of people that are super easy to run a SQL query on that, somehow, no one ever ran a bigger sample.
Are you sure you’ve really considered the plausibility of this statement?
Some do, and more do if they have a more realistic goal than achieving normal BMI, if they appreciate that a much more modest goal accomplishes huge improvements.
In any case the question was is achieving “overweight” (from “obese”) healthy enough, and the answer is a qualified yes. And even with no weight loss any improved lifestyle choices reap health benefits.
Yes. Many. Here’s one:
To be sure, you may be a solid chunk of muscle and, if so, your BMI does probably mean very little. But very few people are Jay Cutler, Ronny Coleman, or Shaq. Very few people have a quantity of muscle that starts to get into the same mass zone as fat and, when you see them, it should be clear to any doctor that, for this person, the BMI isn’t a useful criteria.
But are you actually a mini-Shaq? Or is that whole tale an excuse for being willing to lift heavy but unwilling to reduce your calories and up your walking?
One reason I think people discount BMI is that the visual idea of a healthy weight is subjective. In today’s society, a person who is at the proper BMI will likely be considered skinny, while a person with excessive body fat will be considered at proper weight. To combat this, it would be helpful if an organization put together pictures of various people which showed their BMI and body fat percentages. That would help educate people on what an ideal weight looked like.
There’s a guy who has a goofy blog called cockeyed.com. On it, he has a place where people can specify their height/weight and upload photos. From there, I found this picture of a 5’10" person who weighs 150. That puts him at a BMI of 21.5:
I would guestimate his body fat is somewhere in the 12% range. He’s likely athletic which is helping with his muscle definition, but you can also see that his fat layer is thin. This is what an ideal amount of body fat would look like on a man. But most men have more fat than this. They may think of having higher fat as being the proper and ideal amount of fat. When they see this person, they may think he’s too skinny and needs to gain weight. But in reality, this is the level of fat that would be ideal on a man, and most men who carry extra fat would be medically considered overweight. That’s no surprise in our society. It’s trivially easy to order a full day’s worth of calories in a single fast food meal, and then we eat it at the desk of our sedentary office job. To have body fat in the ideal range will typically require most of us to make an effort to consider our diet and add activity to our day. Having something like a set of pictures of various body types with their stats would help create a more objective view of what a proper amount of fat is.
I think you’re missing the point about the 50 lbs. Based on my height, according to BMI I would need to lose 50 some lbs. in order to get to the “normal” zone. My point is that for me to lose that much weight (over 25% of my current weight) would require either “depleting” myself to the point of being emaciated or lopping off a limb.
I’m not saying BMI is not useful in pointing out that weight should be lost. I agree that I could lose some weight (and my trainer agrees, BTW). It’s the amount of weight that BMI indicates I would need to lose that I have a problem with. (Which is why I believe the BMI calculation is not accurate outside a given height range).
If it’s the healthiest weight then, by definition, it’s not emaciated. (Technically, you can be emaciated at a “healthy” BMI but you have to crash diet so as to maintain a relatively high muscle mass to accomplish that. If you are able to maintain a healthy BMI over the long run, your body would eat any excess muscle and turn you into a normal healthy person. But that’s a very precise and ephemeral situation that isn’t going to apply to anyone who is at a stable body weight. In general, if you feel like a person at the healthiest possible weight looks emaciated, then you’ve taken on a false and harmful belief.)
Your concept of “ideal” and “proper” are arbitrary, and what you propose would cause much more harms than goods.
To some degree it is unfortunately what does happen. People constantly compare themselves to buff images in the media and “diet”, some to eating disorder levels, in response to how their bodies don’t look like that. It is virtually never a behavior that results in better health, physically or mentally.
Much better, to my understanding, is to accept that one need not be thin to be attractive or healthy, and to have less focus on the scale and more on the behaviors. That does not mean that metrics should be ignored, but they are less primary than our day to day actions.
@cormac262 whether or not achieving a so-called “normal” BMI would make you emaciated a serious self evaluation of opportunities to improve your nutrition habits is likely warranted.
@Sage_Rat the concept that there is a BMI that is healthiest for all body compositions is incorrect.
To be sure and I have made that clear in that and in many posts. But, that’s not really the issue in nearly all cases.
First of all, the most important consideration is not your weight but your metabolic health. Excess weight is less concerning if you have normal blood pressure, blood sugar, cholesterol levels and so forth.
If you have excess weight, strength training can help turn fat into muscle. This is helpful even if weight does not change. Cardio and strength training can improve metabolic tests as well as mood and well-being.
Losing weight is difficult. The first goal would be more to improve the above tests, and exercise capacity, rather than lose the X pounds needed to reach some arbitrary BMI category. The existence of BMI does not mean losing, say 5%, would not benefit many people for the reasons given by studies quoted by DSeid.
But although weight is often overemphasized, exercise level, improving bad habits (smoking, excess alcohol, less processed food) and metabolic health are usually more important. Plenty of overweight people are metabolically healthy and the benefits to being fit are huge. A little exercise is dramatically better than no exercise, and several small changes often add up to significance.
Adding onto what @Dr_Paprika said, in terms of actually losing weight, the first steps are generally to improve your diet rather than to cut calories.
If you start eating more satiating food, you’re liable to lose a fair amount of weight just through not feeling so hungry all the time.
Don’t eat anything with added sugars or that’s deep fried and you’re liable to see notable changes, just by choosing to eat one thing rather than another thing; no calorie cutting.
Piling on and summarizing - BMI is a very mixed bag for health prognostication in the “normal” and “overweight” categories. I strongly suspect BRI has more discriminatory power in those groups. But the most discriminatory power would be a few select fitness measures, endorsement of regular exercise inclusive of cardio and strength training, and one of several patterns of healthy eating. I’ll bet on those who do that with a BMI
of 29 over those who score poorly there with a BMI of 22.
I know body-fat indicators are deemed inaccurate. I’m just wondering if they are more accurate in 2024 than the BMA scale as to too much or not enough fat.
Wow. I thought that had died 15+ years ago. What a relic from the early WWW days. And still chugging along. Go Rob!
Thanks for that.