Is BMI an accurate way to know how much I should weigh?
nonachalke
Posts: 1 Member
I looked up my BMI last night and it says I’m overweight, so obviously I’m freaking out. But is it accurate? I don’t want to just lose weight, I want to get toned and strong, I like muscle on me, but how do I know how much I should weigh?!
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Replies
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The purpose of BMI is not to tell a specific individual how much they should weigh. BMI uses standard weight status categories that can help doctors to track weight status across populations and identify potential issues in individuals. It gives a rather large weight range at that. Many of us use it as a general guide for what weight range we want to shoot for. If you are generally fir and healthy and feel comfortable with your current weight, don’t worry about it too much.10
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If you have looked at yourself in the mirror and you don't think you are overweight with excess fat in places, there's a decent chance you are not.
I say decent because perception of what healthy looks like can swing both sides of reasonable.
BMI was never intended for individual analysis - it was meant for population averages.
It can get someone into ballpark if average.
Search for healthy weight and if it includes BMI skip it, there are other measurements and calculations to give a clue if the mirror isn't useful.
ETA:
Found it, past site was gone, but found another offering several of the study formulas that have been developed.
https://www.calculator.net/ideal-weight-calculator.html
I've always found the formula's on the low end if one wants a decent amount of muscle mass.
And there again is any formula that doesn't include BF% can be leaving out healthy or extra amounts of muscle mass.
So....
https://www.calculator.net/body-fat-calculator.html
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Waist size is a good indicator, waist to height ratio or waist to hip ratio. I have a 32.5" waist at a bmi of 24.1, and that's just me doing chin ups and push ups at home for the past two months.
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I would be careful even with that ideal weight calculator... I have a solid muscle mass, am 6'1 and weigh 186.
It tells me my ideal weight is anywhere from 140 - 190.
At my lowest, I was 160 and I was incredibly lean (around 10% body fat). There is no way I could have dropped another 20 and still been healthy.
Right now, I could probably comfortably lose 10-15 lbs... So I do fall in the ideal range, but at the higher end... Not the lower.
If you want to gain some mass, be prepared to sit at the higher end.
But like the other poster said... What do you feel? What do you see in the mirror?
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BMI is designed to give people a range to know where health problems associated with being underweight and overweight start. It is not designed to tell people where they will look and feel their best, although many of us do find that they look and feel their best somewhere in that "healthy" range.
You hear a lot about BMI not being "accurate." Some of that stems from people not understanding what it is for and yes, there are some people who find that it puts them in the overweight or obese category when really they're just heavier due to muscle. But the majority of people in the US who are categorized as overweight or obese aren't in that category due to excess muscle. Let's be real.
(I have no idea if you're in the US or if you currently have a lot of muscle weight, I'm just saying generally).15 -
I looked up my BMI last night and it says I’m overweight, so obviously I’m freaking out.
Why on earth would you freak out? Giving your stats would help, are you well into the BMI overweight range or just over the border?
But is it accurate?
It's a guide. The majority will fit within the very wide ranges but of course there are outliers but they tend to be male and unusualy well muscled. There's far fewer female outliers but they do exist and of course you are an individual so what is a guide for the majority doesn't help much if you are in the minority.
I don’t want to just lose weight, I want to get toned and strong, I like muscle on me, but how do I know how much I should weigh?!
Look in the mirror?
Like what you see and your body performs how you would like it to then be happy.
Post a picture if you want other people's opinion but it's your opinion and your choice that matters.
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It's possible for a woman to be so muscular that she should fall in the overweight body mass index range, but it isn't common. For example, most female Olympic champions are in the normal body mass index category, and that includes some whose sports are strength-centric. I doubt they have low muscularity, in nearly any sport these days (though some of the speed sports do pursue very light bodyweight via body fat percent that would be too low for a non-elite athlete).
https://www.runnersworld.com/health-injuries/a20793992/bmis-of-champions-womens-edition/
Also, for equal opportunity reading: https://www.runnersworld.com/races-places/a20811275/bmis-of-champions-mens-edition/
(Casual readers: Yes, those links are from Runners World. The athletes are not all track & field athletes. Read article before commenting on it, eh?)
I'm used to being around collegiate women rowers (a strength endurance sport) from a high-level program. I know what some of them weigh. They're sometimes surprisingly heavy compared to how they look, but usually in the normal range. (They look pretty ripped when they finish a race, but in their spaghetti-strap dress-up outfits at banquets and such, they just look toned & beautiful. They do leg day with plates the size of freight-train wheels, I swear: Impressive strength.)
In women, body configuration makes a difference, too. For example, woman with well above average breast size and wide pelvis (spacing between the right and left side of the bones) is more likely to find a happy weight on the heavier side (though not necessarily outside the normal range).
Conversely, a more narrowly built woman may be best in the lower part of the normal BMI range, even with some muscularity. I'm no bodybuilder, but not completely devoid of muscle, and I'm best around BMI 20, which is toward the lower end, because I have no breasts (post mastectomies) and narrow pelvic width, even though I have broad shoulders and bigger hands/wrists. (Many of the body frame "calculators" rely on wrist/elbow size, and say I have a medium or large frame. I don't. I'm built more like a 14-year-old boy just entering puberty - broad shoulders, narrow hips - than the 65-year-old woman I actually am. 😆)
I don't have a link - someone may - but there are web sites where you can look at women of different body sizes and compare to make a better guess at your body fat percent, and extrapolate from there. Beyond that, another thing you can do is talk with your doctor about what would be a healthy personalized range, for you.
Keep in mind that if you don't have the muscle mass *yet*, it's a slow build, so you can choose to lose slowly down to a good weight for your current configuration, and then add back a bit as muscle mass increases, or to facilitate increasing it at a faster pace. That might be a good choice if you're truly overweight (i.e., have some excess bodyfat) now, as exercise is a bit easier at a healthy weight (speaking as someone who was an obese athlete a few years back).
*If* you have a good sense of body confidence, you can probably trust yourself to realize when you're a good weight. That's kind of a tentative statement on my part, especially if you're a younger woman: It's somewhat common, sadly, among young women to pursue body goals that have been unrealistically calibrated based on very thin celebrities, models, and IG influencers. Keep in mind that if you do want a female bodybuilder physique, the way they look at competition time is not how they look most of the time, walking around in real life. They lean down a lot, for competitions.
Best wishes!8 -
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If you don't have a lot of muscle, then it's okay. But you could also be very "skinny/fat" and be within the BMI level for your height and weight.
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nonachalke wrote: »I looked up my BMI last night and it says I’m overweight, so obviously I’m freaking out. But is it accurate? I don’t want to just lose weight, I want to get toned and strong, I like muscle on me, but how do I know how much I should weigh?!
For almost everybody, yes it is accurate -
Unless you have have a really high muscle percentage, meaning elite body builder high, or you are some other sort of outlier ( 9 months pregnant, double amputee or some other obvious condition that will skew height/weight ratio) then it is highly unlikely you are at a healthy weight very far out of standard bmi range.
Sure, there are some non outlier people who sit healthily just outside it - but even then not very far out of it.
Can u give us your actual statistics - age, gender, height, current weight?6 -
You don't need to be on the level of an “elite” bodybuilder, if you've been lifting for a year or more you will develop a lot of muscle mass. Most of your gains will occur in the first year assuming you eat right and train hard. If you have gained 20lbs of muscles in your first year, then BMI is unreliable.
As i've said, I have a 32.5 inch waist at a BMI of 24.2, if I gain 4 more pounds i'm officially in the overweight category. And that's just me doing bodyweight exercises for the past months, it doesn't take much
And i'm not even going to delve into the subject of gender and different ethnicities.4 -
You don't need to be on the level of an “elite” bodybuilder, if you've been lifting for a year or more you will develop a lot of muscle mass. Most of your gains will occur in the first year assuming you eat right and train hard. If you have gained 20lbs of muscles in your first year, then BMI is unreliable.
As i've said, I have a 32.5 inch waist at a BMI of 24.2, if I gain 4 more pounds i'm officially in the overweight category. And that's just me doing bodyweight exercises for the past months, it doesn't take much
And i'm not even going to delve into the subject of gender and different ethnicities.
What would be unreliable about my BMI if I gained twenty pounds of anything -- fat or muscle?
What about gender makes BMI unreliable, in your opinion?2 -
If for exemple i'm 5'9 150lbs and 15% body fat, I start lifting and gain 20lbs of muscles. Suddenly I am considered overweight in term of bmi even though my body fat percentage is low.
When it comes to gender, men have less body fat and more muscle mass. For this reason, it doesn't take much for the average man to put on enough muscle mass and for bmi to be unreliable in determining obesity or a surplus of body fat.
I gave my own exemple, there are plenty of others.
Like I said, the exception is not only for elite bodydbuilders or athletes, but just regular people who go to the gym.3 -
Although generally speaking, bmi is useful for both genders if we're talking about sedentary individuals. It appears, according to what I have read, women don't suffer from health problems on the higher end of healthy bmi.1
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If for exemple i'm 5'9 150lbs and 15% body fat, I start lifting and gain 20lbs of muscles. Suddenly I am considered overweight in term of bmi even though my body fat percentage is low.
When it comes to gender, men have less body fat and more muscle mass. For this reason, it doesn't take much for the average man to put on enough muscle mass and for bmi to be unreliable in determining obesity or a surplus of body fat.
I gave my own exemple, there are plenty of others.
Like I said, the exception is not only for elite bodydbuilders or athletes, but just regular people who go to the gym.
At 5'9 and 170 pounds, your BMI would be considered .1 into the overweight category, so you've constructed an edge case that would immediately be addressed by your health care provider combining this with a simple waist measurement to give you the proper guidance. What's a more common problem in the west right now -- someone being 25.1 with 15% body fat and receiving the inappropriate guidance to lose weight or someone genuinely overweight?
Keep in mind that the BMI is a population-level analysis and it isn't supposed to be an ultimate guide to whether or not an individual needs to lose weight. Not too many people are in the situation of being a "regular person going to the gym" and adding twenty pounds of muscle "suddenly."
The CDC already accounts for the fact that men and women will tend to have different body fat levels at the same BMI. Given that this tool is designed to be combined with other assessments, what again is the exact concern?6 -
I could give another exemple, if I was 5'9 160lbs at 18% bf and gained 20lbs of muscles I would be 10lbs overweight according to bmi even though my body fat percentage would have gone down due to the increased muscle mass. Many people go to the gym or do resistance training at home, it isn't unusual and we're talking about men particularly because they have greater capacity for muscle building due to hormones. Women on average gain 10lbs of muscles the first year compared to 20lbs for men.
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I could give another exemple, if I was 5'9 160lbs at 18% bf and gained 20lbs of muscles I would be 10lbs overweight according to bmi even though my body fat percentage would have gone down due to the increased muscle mass. Many people go to the gym or do resistance training at home, it isn't unusual and we're talking about men particularly because they have greater capacity for muscle building due to hormones. Women on average gain 10lbs of muscles the first year compared to 20lbs for men.
And in that example, your doctor would still be taking your overall physical state into account and giving you guidance based on that, not the fact that you were in the overweight range on the BMI scale. So what's the exact issue you're concerned about here?
The point is that MOST men in the west who are 5'9 and 180 aren't in danger of being falsely classified as being overweight when the point is that they've just put on 20 pounds of muscle through resistance training at home. They aren't in danger of mistakenly assuming they're overweight. The more prominent issue is that men (and women) ARE overweight.
Those people who are putting on twenty pounds of muscle at home know very well what they're doing and they aren't going to panic because they think they're overweight. You're addressing a problem that doesn't really exist, while the problem of people calculating their BMI and deciding they aren't REALLY overweight because they're sure it's all just muscle and "everybody knows" that BMI is useless is a much more real concern.10 -
I was replying to someone who was talking about “elite” bodybuilders, when it is much more broad than that. That was the point of my post. When I started weight training 15 years ago a personal trainer said the same thing to me, that it only applies to bodybuilders or athletes. It is nonsense.
The point is you don't need to be a high level athlete or anything, in certain cases it can be a guy who has been lifting weights for 6 months.
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If you are talking to me - in my post about elite body builders being outside the range I also said there are some non outlier people ( ie people who are not elite body builders, 9 months pregnant, amputees etc) who sit slightly outside the range.
I am also on record on this forum as saying sporty young men ( not body builders, just fit sporty young men) are often healthy just outside the range with BMIs around 27.
Thaf might be a guy who has been lifting weights for 6 months - but he still wouldn't be very far outside the range.
None of that negates BMI as a good tool for almost all of us, like I said.
Not really sure what your argument is.
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paperpudding wrote: »
I am also on record on this forum as saying sporty young men ( not body builders, just fit sporty young men) are often healthy just outside the range with BMIs around 27.
Thaf might be a guy who has been lifting weights for 6 months - but he still wouldn't be very far outside the range.
I didn't know you said that, I haven't read all of your posts. I was replying to your post about elite bodybuilders, i'm well aware that bmi is useful for sedentary individuals.
And I don't know what you mean by far outside the range, but after 2 years of weight lifting I had a healthy percentage of body fat at a bmi of around 28. That is quite a bit outside the range. Nowhere close to elite bodybuilder status.
Also when it comes to ethnicity, it is clear that the bmi index and its consequences are different for certain demographics :
https://www.hsph.harvard.edu/obesity-prevention-source/ethnic-differences-in-bmi-and-disease-risk/
“China and Japan define overweight as a BMI of 24 or higher and obesity a BMI of 28 or higher; in India, overweight is defined as a BMI of 23 or higher, and obesity, a BMI of 27 or higher”
“In contrast, some studies have found that blacks have lower body fat and higher lean muscle mass than whites at the same BMI, and therefore, at the same BMI, may be at lower risk of obesity-related diseases.”
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BMI is meant to be a general guide, when taken into consideration with other metrics like waist measurement, body fat %, and blood work and other medical metrics. It is a good general guide for the vast majority of people. But it is no guarantee of predicting a healthy weight for every individual, it's not intended to be. The fact that there are outliers doesn't make it useless.
If you've had a physical and gotten a clean bill of health recently, and your waist measurement is within the healthy range, then being slightly over the healthy BMI might not mean anything.
It is doubtful anyone would be an outlier without realizing it. If you are very tall, very short, or heavily muscled you may be at a healthy weight while outside the BMI range. If you're concerned, get a physical and blood work and discuss it with your doctor.
Unfortunately it is not uncommon for people to convince themselves they are "muscular" because they go to the gym sometimes, or have a naturally large frame and muscular build, when they really are just overweight. If you are outside the healthy weight range and think it's because you are muscular but have no idea what your bf % is, consult a pro to confirm that. Or if you're happy where you are, and your doctor is unconcerned, just don't worry about it. BMI isn't intended to be the be all and end all, just one of several data points.
"Health" is not a yes or no question, it's a sliding scale. How much of a health risk extra weight conveys is still an open scientific question - all we have is correlation. What is healthy enough for your priorities and comfort level is a personal decision. There's no harm in eating at a deficit for a couple of months, losing a few lbs, and seeing how you feel and look and going from there. If you lose weight slowly, you shouldn't lose appreciable muscle. Regardless, it's certainly nothing to panic about
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I agree with all of that, it is not useless, it's probably useful for 90% of the population. And there are a lot of questions, for exemple, what is the percentage of the population who lift weights or do resistance training on a regular basis?2
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Im afraid I still dont know what your argument is - nobody, certainly not me, was arguing that ethnic groups cannot have slightly different ranges of healthy BMI
You dont have to have read my posts in other threads - I said in this thread some people are slightly out of the range and still healthy.
My further post just gave an example, which I have used before.
Very few people, unless obvious outliers, will be a healthy weight very far out of standard BMI range.
Not just sedentary people - all people.6 -
What is very far out of standard BMI range? If we're talking about a bmi of 27 versus a bmi of 25, that's a difference of 15lbs. It is quite significant don't you think?
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No I don't.
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Is a bmi of 29 very far out of the healthy range? We're talking about a difference of 25lbs, about what a man can gain in muscle mass with a year of training.0
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paperpudding wrote: »nonachalke wrote: »I looked up my BMI last night and it says I’m overweight, so obviously I’m freaking out. But is it accurate? I don’t want to just lose weight, I want to get toned and strong, I like muscle on me, but how do I know how much I should weigh?!
For almost everybody, yes it is accurate -
Unless you have have a really high muscle percentage, meaning elite body builder high, or you are some other sort of outlier
I will have to quote you, because even an experienced lifter who's healthy at a bmi of 30 is not elite bodybuilder status. I guess i'm a little bit confused by your choice of words.
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I think what I said is quite clear, sorry if you find it confusing.
Not getting caught up in semantics of word choices. You can play that game by yourself.5 -
nonachalke wrote: »I looked up my BMI last night and it says I’m overweight, so obviously I’m freaking out. But is it accurate? I don’t want to just lose weight, I want to get toned and strong, I like muscle on me, but how do I know how much I should weigh?!
I think BMI is a pretty good target to aim at. Is it the be all and all? No.7 -
I agree with all of that, it is not useless, it's probably useful for 90% of the population. And there are a lot of questions, for exemple, what is the percentage of the population who lift weights or do resistance training on a regular basis?
A recent study reported that 8.9 percent of Americans had done some kind of weight lifting in a typical day (this seems high to be, but what do I know?). The number of people who are doing it at a level to drive their BMI into the overweight range even though their body fat is at a healthy level is not recorded, but it's going to be much, much less than that. In contrast, 2/3s of Americans are in the overweight or obese range. We're not dealing with a nation of Dwayne Johnsons being falsely diagnosed with obesity. We're talking about a whole bunch of overweight people. I don't have the stats for Canada, but I am not aware of any evidence showing it's an issue there either.9
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