BMI vs percent body fat????
hrsj022
Posts: 41 Member
Even before I started MFP I went to the Doctor. I got weighed he looked at the chart and said no way you weigh that...the nurse must have mixed this up. So the Doctor weighs me and is shocked. He said well you don't look your weight...anyway fast forward to today...on the BMI I'm severely Obese a 42 on the percent of body fat I'm at 28% so it's supposed to be considered acceptable? So which is more important I'm confused!!! Help
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Unless you are an athlete, and in a sport that helps you build a lot of muscle, you are morbidly obese and the fat percentage measurement is inaccurate. There is no way a BMI of 42 places you anywhere close to healthy weight. Even if you are a bodybuilder.0
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I'm in a similar situation to yourself. My BMI puts me a few points off of obese. However, my Body fat % is 35, and should be max 30, which i dont think is too bad considering what i used to weigh.I have lost over 4 stone, workout 5/6 days a week, including regular weight training. I have gone from a Uk size 20 to a UK size 10-12. There is no way i will accept my BMI of almost obese at a bloody size 10!! Similarly my partner, who works out with me, has a body fat % at the lower end of his 'healthy' range, i literally cannot pinch any fat anywhere on him, and yet he is also deemed as obese. I still weigh in, but dont pay as much attention to it, i now measure my fat % once a week at the gym and use that to track my progress.0
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How did you come up with the BF% ?
I'm a little skeptical on the BF% OP. If you were using a scale remember that method is considered highly inaccurate for determining BF%. Dexa scan, bod pod, and dunk tests are considered to be the most accurate methods.
My husband gets a reading of 10% from the scale he uses, but a caliper measurement by a trainer at the gym puts him closer to 20%. Looking at him, I think the 20% measurement is closer to being accurate.0 -
Scales at gym0
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BMI is BS, pay it no mind.
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When I first started I was obese according the charts as well. And that was over a year ago. But now, I'm down to 23% bf. Just keep going and use the scale at the gym as a tool. It's more than likely inaccurate, however if it goes down that's great. You know you are working in the correct direction.
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the body fat percentage scales are notoriously inaccurate. If they are ones you just stand on they only measure the lower half of you, even the ones used by the gym that do your whole body are not that accurate, it depends on how hydrated you are etc. The only real way to get a body fat % is to get a PT or Dr to use calipers to measure. As for BMI its an ok rule of thumb unless your an athlete with lots of muscle.
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I had a check at the gym the other day that put my BF% at 40% (with one of those handheld gadgets)!!
My BMI is 24.8 so I'm in healthy range and calipers method and tape measure method put me around 26% BF
I won't be touching their gadget again!0 -
samhennings wrote: »BMI is BS, pay it no mind.
False. It is a decent indicator for around 80% of the population. If you have lifted for a long tI'm and/or do manual labor someone with a bmi over normal may have an acceptable bodyfat percentage. Otherwise probably not.0 -
shadow2soul wrote: »How did you come up with the BF% ?
I am wondering the same thing. A BMI of 42 at an average height of 5'6" is 260lb. I don't think you could have 200lb of lean body mass, unless you have bones made of lead or something that doesn't make sense.0 -
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I would toss BMI out the window. It may be good for 80% of the population but body fat percentage works for 100% of the population. That said, getting spot on accurate BF% is pretty hard to do unless you use calipers or water displacement. The electric current/resistance body fat calculators can be pretty accurate to a complete waist of time. You can get within +/- 1.5 BF% with honest measurements. I say honest because you need to measure in the right place, every time to get accurate results. I also recommend you get someone else to tape you. That way your movements are not throwing off the results. Take three measurements of each area, average the results and the plug that into the calculator.
All of the measurements are also great NSVs for those looking to gain muscle and/or lose weight. Dropping an inch in the waist or hips is cause for more celebration than just losing a few pounds.0 -
^This.hypnobabe67 wrote: »the body fat percentage scales are notoriously inaccurate. If they are ones you just stand on they only measure the lower half of you, even the ones used by the gym that do your whole body are not that accurate, it depends on how hydrated you are etc. The only real way to get a body fat % is to get a PT or Dr to use calipers to measure. As for BMI its an ok rule of thumb unless your an athlete with lots of muscle.
I've stepped on a scale at a friend's place that measures body fat %. It told me I was 28% when at the time I was probably between 12-14%.
A month ago I started cutting for summer and tried measuring my starting weight and body fat. I used a thing at the grocery store that you sit on and put your palms out onto a few metal strips and I'm guessing it sends electrical pulses through you. That told me 24%. Not 1 hour later I used caliphers at home and depending on the formula used I was given anywhere from 12% - 18%. Eyeballing myself I think 15-18% was the most accurate but unless it's professionally done the results are going to be all over the place.
I agree, BMI is fine for non-athletes. Right now my BMI is 26 which puts me in the overweight category but a quick look through my photos on this site will tell you that I'm certainly not overweight.0 -
Even before I started MFP I went to the Doctor. I got weighed he looked at the chart and said no way you weigh that...the nurse must have mixed this up. So the Doctor weighs me and is shocked. He said well you don't look your weight...anyway fast forward to today...on the BMI I'm severely Obese a 42 on the percent of body fat I'm at 28% so it's supposed to be considered acceptable? So which is more important I'm confused!!! Help
What's your frame size? http://www.myfooddiary.com/Resources/frame_size_calculator.asp
I have a large frame and the only time I've had a BMI of 24 was after 6 weeks of under-eating and over-exercising during Boot Camp.
That said, with a BMI of 42 you're still overweight, but perhaps not Severely Obese if you do have a large frame.
Where'd you get your body fat tested? Many ways to measure this are not considered accurate. http://dailyburn.com/life/health/how-to-measure-body-fat-percentage/0 -
Not to hurt your feelings but I do think there is SOME correlation from bmi to a rough body fat percentage.. Like the only cases where bmi is way off are in professional athletes ( or competitive athletes) aka 2-5% of the population, and in taller folks ( like me who's 5'10). I have found when my body fat goes down so does my bmi. People will always say you look like you weigh less because everyone lies about their weight.. No one ever guesses I weigh 130s or 140s because I'm so tall and athletic. Lots of people are frauding on their weight and it gives lots of people like you false confidence.0
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Also it's possible he saw the weight and was shocked at such a high number. One time as a child I gained ten pounds and the number was quite high and my doctor had a similar reaction. A bmi of 42 is very overweight might even be morbid obese. There's a chance he doesn't get morbid obese patients day to day and was up equipped to handle it0
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Scandinavianblonde wrote: »Not to hurt your feelings but I do think there is SOME correlation from bmi to a rough body fat percentage.. Like the only cases where bmi is way off are in professional athletes ( or competitive athletes) aka 2-5% of the population, and in taller folks ( like me who's 5'10). I have found when my body fat goes down so does my bmi. People will always say you look like you weigh less because everyone lies about their weight.. No one ever guesses I weigh 130s or 140s because I'm so tall and athletic. Lots of people are frauding on their weight and it gives lots of people like you false confidence.
I had a similar experience when I was doing online dating and most of the men were adding a few inches to their height. However, the OP is talking about a doctor seeing patients who weigh on a medical scale in his office, not people self reporting their weight.0 -
BMI works for the vast majority of the population. Ignore at your own risk.0
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OP, without providing your height and weight, we would only be guessing. Also, how did you measure your body fat %? The two numbers you provided seem really hard to reconcile.0
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They should be used in conjunction with BF% being more specifically important to an individual, however, your numbers just don't jive at all. It is not uncommon for people who train, to be overweight by BMI standards but to be well within a healthy BF%...but there's way too much disparity in your numbers, even if you were a professional body builder.
Just as an example, I have a BMI of 26.4 which puts me just over the line of overweight...I'm somewhere between 12-14% BF which is well within a healthy range for a male of my age....but there's just not a huge disparity here between my BMI and my BF%...to get to the highest end of a healthy BMI, all I'd need to do is drop about 9 Lbs...which would also have me very lean...probably 8-10% BF.
Something isn't right with your numbers...my guess is that you are not measuring your BF% properly.
By and large, BMI is a pretty good indicator for the vast majority of the population...and even if you train, unless you're an elite athlete of body builder or something, there shouldn't be a whole lot of disparity between what BMI is telling you and your BF%.0 -
shadow2soul wrote: »How did you come up with the BF% ?
I'm a little skeptical on the BF% OP. If you were using a scale remember that method is considered highly inaccurate for determining BF%. Dexa scan, bod pod, and dunk tests are considered to be the most accurate methods.
My husband gets a reading of 10% from the scale he uses, but a caliper measurement by a trainer at the gym puts him closer to 20%. Looking at him, I think the 20% measurement is closer to being accurate.
My Aria scale puts me at 28% body fat. I have no idea how close that is, but I assume its off considering the scales are widely known to be inaccurate.
I've never done a scan, but I'm thinking about it.
OP, no way you have a 42 BMI with 28% body fat.0 -
Sorry, hun. That body fat % is wrong.
If anything excluding special populations such as bodybuilders or athletes, body fat has a pretty damn strong correlation with bmi.
If you have such a high bmi i'd say it's pretty likely you fall into that range for body fat (40%~) as well.0 -
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shadow2soul wrote: »How did you come up with the BF% ?
I'm a little skeptical on the BF% OP. If you were using a scale remember that method is considered highly inaccurate for determining BF%. Dexa scan, bod pod, and dunk tests are considered to be the most accurate methods.
My husband gets a reading of 10% from the scale he uses, but a caliper measurement by a trainer at the gym puts him closer to 20%. Looking at him, I think the 20% measurement is closer to being accurate.
My Aria scale puts me at 28% body fat. I have no idea how close that is, but I assume its off considering the scales are widely known to be inaccurate.
I've never done a scan, but I'm thinking about it.
OP, no way you have a 42 BMI with 28% body fat.
Ya. I use an Aria and it estimates about 22% for me. I think I'm probably closer to 26%. It's been awhile since I had caliper measurements done and it would take a drive into the city for any other tests.0 -
shadow2soul wrote: »shadow2soul wrote: »How did you come up with the BF% ?
I'm a little skeptical on the BF% OP. If you were using a scale remember that method is considered highly inaccurate for determining BF%. Dexa scan, bod pod, and dunk tests are considered to be the most accurate methods.
My husband gets a reading of 10% from the scale he uses, but a caliper measurement by a trainer at the gym puts him closer to 20%. Looking at him, I think the 20% measurement is closer to being accurate.
My Aria scale puts me at 28% body fat. I have no idea how close that is, but I assume its off considering the scales are widely known to be inaccurate.
I've never done a scan, but I'm thinking about it.
OP, no way you have a 42 BMI with 28% body fat.
Ya. My husband uses a different scale than me. I use an Aria and it estimates about 22% for me. I think I'm probably closer to 26%. It's been awhile since I had caliper measurements done and it would take a drive into the city for any other tests.
Anecdotally, having done calipers and having had a couple hydrostatic weigh ins....
My real bf% is around 18-19%.
My handheld body fat reader and scale both put me around 24-25, all the way down to 14-15 depending on my hydration levels. if that's any indication as to how wildly off they can be.0 -
If you are BMI of 42, it is all but impossible that you are below 40% body fat.
A body fat of 28% would mean you have a fat free mass index of over 30. Maximum observed fat free mass index in natural male body builders (Mr. Olympia level) is around 25.4.0 -
Ultimately, the only important question is are you of a healthy weight/body composition?
I mean, do you have weight to lose and if so, how much? Do that and then reevaluate.0 -
If you are BMI of 42, it is all but impossible that you are below 40% body fat.
A body fat of 28% would mean you have a fat free mass index of over 30. Maximum observed fat free mass index in natural male body builders (Mr. Olympia level) is around 25.4.
This. 330 lb 6'2" NFL defensive linemen are generally in the 20-25% BF range.0 -
shadow2soul wrote: »How did you come up with the BF% ?
I am wondering the same thing. A BMI of 42 at an average height of 5'6" is 260lb. I don't think you could have 200lb of lean body mass, unless you have bones made of lead or something that doesn't make sense.
This is what I was thinking. The math doesn't add up.
The only thing I find valuable about the body % report on my Aria is watching trends. Even then it goes up and down a bit (I'm guessing depending on my water content at the time), but as long as I weigh myself in the morning before I eat or drink anything, I can usually follow a trend, and see it go down as my weight goes down. But I'm also following the trend of my weight going down, it's pretty much irrelevant. I know any muscle I'm putting on is at a very slow rate as I'm not doing significant bodybuilding training, so without the help of a trained professional using callipers to measure my % body fat, BMI is the best way for me to track my progress toward a healthy weight.0 -
@kshama2001 That chart is very helpful! Thank you for sharing!0
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