BMI accuracy

Amandalynn380 · February 2016

Hi all,

So I'm 5ft 4 inches and my weight fluctuates between 145 and 148. According to my BMI I'm over weight . I had a beautiful baby boy a year ago. Before I had him I was 135. Even though I've lost about 20 pounds since he was born, Ive been feeling pretty down about my BMI indicating that I'm overweight . Is BMI really that accurate? Should I really base my goals off of that?

farbs · February 2016

I personally don't like to use BMI as an indicator. It doesn't seem to take everything into account, like weight from muscle etc. My brother, for example, comes up as obese. He's 176 cm and quite muscly. He is in no way obese in my opinion...but that's what BMI tells him. I'm obese too apparently. I would have thought overweight, not so much obese.

I guess obese is a specific term used for the BMI, but when I think of that term, I think of someone who is very overweight.

Just my view on it.

richardgavel · February 2016

I think BMI is good as a rough indicator of where you should be, unless you fall outside the norm (like someone who is very muscular). But once you get inside the normal range, then start to focus more on how you look in the mirror or body fat % or other measures. I did use BMI to set an initial weight goal to shoot for, so I had SOME idea of what I should target.

shadow2soul · February 2016

At the low end of your range, your a healthy weight and only considered slightly overweight by BMI at the higher end.

But ignoring BMI for a moment, are you happy with how you look? Are you ok with what you see in the mirror? If the answer is yes, then what does it really matter what BMI says. While I don't believe BMI is completely useless, I don't think you should give it power over how you feel about yourself. If your happy with how you look at your current weight range, maintain there. Base your goals off of how you feel (as long as it doesn't take you underweight :flowerforyou: )

Sued0nim · February 2016

It's not about aesthetics but health measures ...it's a population measure and wasn't designed to be used on an individual basis

For 70% of the population thoughit's a good guideline

So are you an outlier? It's doubtful TBH, although most overweight people seem to believe they are because it's comforting

Your body changed after birth ...you should probably decide if you're carrying superfluous fat around your middle

Personally I'd aim for a BMI of 25 and see where I go from there

Amandalynn380 · February 2016

Im not too far from 25 BMI, I think that's a goal I can achieve .

ElJefeChief · February 2016

If you have a high degree of lean body mass (e.g., if you're an elite athlete or bodybuilder), the BMI loses validity as an indicator of health. Otherwise, it's generally accurate, with the caveat that more contemporary data from the CDC tends to indicate that slightly overweight people have better health outcomes (e.g., mortality) than normal or slightly underweight people. Which I always thought was artifactual, but that's just me.

paperpudding · February 2016

Yes BMI needs to be take in context but generally it is a good guide.
But If you are very muscular it can artificially put you into overweight when you are a healthy weight.

Are you very muscular OP?

I know when I had a BMI of 28 it wasn't because I was very muscular. BMI I said I was overweight because I was overweight.

coreyreichle · February 2016

Amandalynn380 wrote: »

Hi all,

So I'm 5ft 4 inches and my weight fluctuates between 145 and 148. According to my BMI I'm over weight . I had a beautiful baby boy a year ago. Before I had him I was 135. Even though I've lost about 20 pounds since he was born, Ive been feeling pretty down about my BMI indicating that I'm overweight . Is BMI really that accurate? Should I really base my goals off of that?

Yes, it is, unless you are an elite athlete.

At worst, it underestimates. Many folk in the "health range", are in fact, obese by bf%.

coreyreichle · February 2016

farbs wrote: »

I personally don't like to use BMI as an indicator. It doesn't seem to take everything into account, like weight from muscle etc. My brother, for example, comes up as obese. He's 176 cm and quite muscly. He is in no way obese in my opinion...but that's what BMI tells him. I'm obese too apparently. I would have thought overweight, not so much obese.

I guess obese is a specific term used for the BMI, but when I think of that term, I think of someone who is very overweight.

Just my view on it.

This is a male, 5'9", and overweight by BMI (Not obese):

https://images.t-nation.com/forum_images/e/1/e17b6_ORIG-kenyattaw3fx9.jpg

So, unless your brother looks like him, he's overweight, if not obese.

3dogsrunning · February 2016

BMI is not meant to be accurate. It is a guideline, a screening.

"BMI does not measure body fat directly, but research has shown that BMI is moderately correlated with more direct measures of body fat obtained from skinfold thickness measurements, bioelectrical impedance, densitometry (underwater weighing), dual energy x-ray absorptiometry (DXA) and other methods. Furthermore, BMI appears to be as strongly correlated with various metabolic and disease outcome as are these more direct measures of body fatness"

"A high BMI can be an indicator of high body fatness. BMI can be used as a screening tool but is not diagnostic of the body fatness or health of an individual.

To determine if a high BMI is a health risk, a healthcare provider would need to perform further assessments. These assessments might include skinfold thickness measurements, evaluations of diet, physical activity, family history, and other appropriate health screening"
http://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/index.html

ClosetBayesian · February 2016

At 145, your BMI is 24.9, so not overrweight. At 148, you're overweight by a whopping three pounds.

murp4069 · February 2016

I've been using BMI as a guideline for deciding my goal weight range, but that's really it.

Lounmoun · February 2016

Amandalynn380 wrote: »

Hi all,

So I'm 5ft 4 inches and my weight fluctuates between 145 and 148. According to my BMI I'm over weight . I had a beautiful baby boy a year ago. Before I had him I was 135. Even though I've lost about 20 pounds since he was born, Ive been feeling pretty down about my BMI indicating that I'm overweight . Is BMI really that accurate? Should I really base my goals off of that?

I'm the same height and for me BMI is a good indication of the range where I should be considering where I felt and looked my best in the past.
You are only 3 lbs overweight so if you stay there it probably isn't having an impact on health like if you were 20-50 lbs overweight. No one just looking at you knows you are 148 vs 145. Did you feel better when you were 135 lbs than you do now? Focus on getting to a weight you feel good at this point but don't stress about it.

peleroja · February 2016

There is no magic process in your body that makes 148 a bunch more dangerous than 145 just because BMI says the former is overweight and the latter is normal.

That said, there is a healthy "range" for a reason, and for most people (except elite athletes with a lot of muscle and low body fat, and if you're a woman with 17% body fat and a ton of muscle, you'd know it by your visible abs and rock-hard glutes

) will be at their healthiest weight and most appropriate body fat percentage within that range. On the whole, as women tend to have higher body fat and lower muscle mass, we are as a population more likely to be healthiest in the lower part of the range, but there are certainly outliers and women who maintain healthy, muscular, athletic-body-fat-percentage weights in top of the healthy range and into low overweight.

I will also say that I'm your height and my highest weight was about 145. At that point, I definitely felt overweight even though my body fat was distributed pretty well (bust and hips, I still had about a 27" waist.) I'm pretty small-framed with a narrow ribcage, shoulders, wrists, small hands and feet, and while I never did a skinfold test or anything at that weight I know my body fat couldn't have been in an ideal range at that point. For me, I look and feel better around a 19.5-20 BMI (so somewhere between 115-120 lbs) even after adding in tons of exercise. I'm stronger, faster, more energetic, and happier lower down the scale even though I wasn't really "overweight" near the top. However, that's me and my body and I've never had kids and I like to run, which is a sport that's much easier when you're on the light side.

kshama2001 · February 2016

@Amandalynn380 what's your frame size? http://www.myfooddiary.com/Resources/frame_size_calculator.asp

Burger2066 · February 2016

Like others have said, it is a good guideline to follow in addition to other factors, but not the end all. 2 years ago I went to a new doctor that uses BMI more than my previous doctor did. He told me that I was borderline obese based on it because I was 212 pounds, but my bf% was under 13% at the time. He kept harping on me about it anyway and wanted me to drop down to 165 pounds (I'm 5'11") which would put me at 23 on the scale. We came to an agreement that if I kept my bf% low, I was fine at 200-205 since everything else was checking out fine. I like to set my weight and body fat goals based on how it makes me feel at those targets (both physically and mentally), if I'm able to do everything I want to do from a life and fitness standpoint (keep up with my kids, not feel groggy, play sports, etc.), and if my blood work comes back good. Those factors mean a lot more to me than a BMI scale.

jeepinshawn · February 2016

Burger2066 wrote: »

Like others have said, it is a good guideline to follow in addition to other factors, but not the end all. 2 years ago I went to a new doctor that uses BMI more than my previous doctor did. He told me that I was borderline obese based on it because I was 212 pounds, but my bf% was under 13% at the time. He kept harping on me about it anyway and wanted me to drop down to 165 pounds (I'm 5'11") which would put me at 23 on the scale. We came to an agreement that if I kept my bf% low, I was fine at 200-205 since everything else was checking out fine. I like to set my weight and body fat goals based on how it makes me feel at those targets (both physically and mentally), if I'm able to do everything I want to do from a life and fitness standpoint (keep up with my kids, not feel groggy, play sports, etc.), and if my blood work comes back good. Those factors mean a lot more to me than a BMI scale.

Thats a good post. I too have been struggling with the BMI charts. I'm right at 25, so slightly over weight. I asked my doctor about it, he did blood work and it all came out fine. He gave me a physical examination, checked out skin folds and said I had a better then average amount of muscle, a larger frame, and that there was no reason for me to be concerned.

Most of the recent studies are showing huge amounts of people are misclassified by BMI, many people who are a 24 or 23 are actually overweight or obese by BF standards, and many people who are over weight are actually quite in good shape. As already noted above those with the best mortality rates seem to hover around 25 or so on the BMI charts anyway...

This is hard to accept, I'm still working on it myself, but if your body can do everything you need it to and you are happy with what you see in the mirror don't worry about any number on the scale or chart and focus on being happy. For instance now I can run for an hour straight, jump on the pull up bar and do 5 pull ups, and crank out pushups like there is no tomorrow. Im burned out on worrying about weight and BF% and just trying to maintain an active healthy lifestyle and continue on with my physical training to help promote that.

joeyzuraski · February 2016

I try to focus on the body fat more than the BMI. Some individuals are obese but they are very muscular developed. Body Fat is more dangerous than how much you weigh because it leads to issues like diabetes down the road. It's best to focus on aiming for how low can you get your body fat percentage than worry about the weight. Because your fat can weigh more than your body can handle.

kaylasaurus · February 2016

As others have said, unless you are highly muscular it is a fair indicator of a weight range. There are always exceptions though - for example my boyfriend is 6'1 ~220lbs which gives him a BMI of 29 (almost obese) but he is very muscular and sits at about 12% bf at this weight. Me on the other hand, I am 5'1 and 96lb which means I have a BMI of 18.1 (slightly underweight) I have 17% bf. So we are the weird ones. Really I wouldn't place too much emphasis on it - maybe you can get your Body Fat tested because the amount of lean mass you have is much more important.

VitaSh · February 2016

If you can get your body-fat and lean muscle measured maybe by a high-quality scale or bodpod , etc that's the best way to track it imo. My BMI says I'm borderline overweight and I'm about 18 percent body fat and quite a bit of muscle.

Rosyone · February 2016

Amandalynn380 wrote: »

Hi all,

So I'm 5ft 4 inches and my weight fluctuates between 145 and 148. According to my BMI I'm over weight . I had a beautiful baby boy a year ago. Before I had him I was 135. Even though I've lost about 20 pounds since he was born, Ive been feeling pretty down about my BMI indicating that I'm overweight . Is BMI really that accurate? Should I really base my goals off of that?

BMI is a population metric and good for setting a side-of-the-barn type weight goal when you're significantly outside the healthy range. But it's not much help when the time comes to fine tune your ideal weight. The variance between individuals is too high for that.

BMI accuracy

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