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If you look at charts they will all say that I'm obese or worse. I'm 6'1" ~250 (dropping to 240) but I'm not "fat".

These charts seem to base it on the fact that my weight vs my height is not in proportion. According to those charts I should be 150-170 (which IMO is far too small. Not to offend anyone.)

Shouldn't this be based on body fat % instead of weight vs height? What body fat % should be considered obese?

Or is the term obese not meaning "fat" but "weight overall relative to what your heart can handle" which would have those charts making more sense.

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Argh you and your weird American unit system... What the heck is 6'11"? :P –  Ivo Flipse Mar 11 '11 at 23:28
    
@Ivo about 182cm (6 foot 1) –  Chris S Mar 11 '11 at 23:39
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185, I think? google.com/search?q=6+foot+1+inch+in+cm –  Ben Alpert Mar 11 '11 at 23:51
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BMI would put you at ~165 lbs, "healthy" range is 142-189 for 6'1". That's definitely low, though; beyond the fact that BMI only works for people of average build, it also only works for people of average height. You're too tall for it :P –  Matthew Read Mar 12 '11 at 2:38
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While I agree with most of the comments and answers pointing out extremely muscular people should not trust on their BMI (alone) to decide if they are considered obese. However, if you're not extremely muscular, a BMI is above 35 or worse 40, is a very strong indicator that you are indeed obese. –  Ivo Flipse Mar 12 '11 at 12:15
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2 Answers

up vote 7 down vote accepted

The Simple BMI is the one which doesn't take the ratio of lean to fat mass into consideration. If you are athletic or muscular it has less value than if you are not.

Obese means you are carrying an unhealthy amount of weight as fat. So a true measure would have to include body fat %.

The reason the Simple BMI exists is it is good as a "general" measure. When I weighed nearly 300 lbs, I would frequently remark that BMI was meaningless without fat % consideration. However I acknowledged that it was probably closer to accurate for me than it would be if I was heavily muscled and athletic.

There are BMI calculations that take body fat % into account, but to make use of them you need some way to reliably measure your body fat%. There are many methods, but discussing them is out of scope for this question.

ASIDE: For the record, I'm an endurance athlete now. I'm 6'2" and weigh 175 lbs with a body fat % hovering around 10%. You do not offend me, but I am not too small by any stretch. I wear size small mens t-shirts but I get funny looks when I say so because I have a long torso and am fairly broad chested. I will acknowledge that I'm not particularly muscular above the waist.

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For our metric friends, I'm 1.88 meters and 79kg –  jdigaetano Mar 11 '11 at 23:40
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BMI was invented for use in statistics. Essentially, the edge cases that BMI does not apply to account for a small percentage of large populations so as to be statistically insignificant. It is useful, then to determine what percentage of the Manhattan area is obese, but not useful when applied individually for you. –  Berin Loritsch Jan 13 '12 at 15:35
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I'm 6.1 and 196 lbs (89kg) and according to BMI overweight too. The BMI measurement claims for my height I should be 82kg, in order to simply not be obese. This measurement doesn't factor in that muscle weighs more than fat. It's such a stupid measure of obesity but is still used in gyms, by doctors and health insurance. It shouldn't be taken as an exact measurement point, but a guide to get within.

Ivo has a good answer on body fat measurement here. Unless you happen to be a student on a University course for nutrition/fitness and have access to the modern measurement techniques that outdate BMI, sticking to BMI is good enough but give it quite a bit a approximatation, I use +- 4kg.

Update
Here's an interesting new alternative to BMI called BAI (from this article on obesity)

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Also good to point out is that BMI is about as accurate as a bioelectrical impedance meter. With an error range between about 4.5-6.5% which indeed would equate to about 4kg in your case! :-) –  Ivo Flipse Mar 12 '11 at 12:09
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