Weight Loss Support - Discrepancy between BMI and Body Fat Percentage

Thin Desire
05-21-2010, 03:37 PM
Has anyone ever measured there Body Fat Percentage? I did the measuring one the other day, where you measure your wrists and your waist and thighs and such, and there's a huge discrepancy. And, I was wondering if anyone else can relate.

I took both the U.S. Army and the U.S. Navy formulas. I find the U.S. Navy formula slightly more believable. According to the USA Format, I'm at 33.65% body fat, and the U.S. Navy formula is 44.30%.

Which gives me a BMI waist-to-hip ratio of >1.2. To be an obese man, it's over >.9 and on a woman it's >.85.

According to the Army formula, this gives me a lean body mass of 191.6 lbs, and the U.S. Army formula is 160 lbs, which I find more believable.

But if I were to believe these numbers, basically I BARELY qualify to be obese in terms of Body Fat Percentage, and yet my BMI shows that I am most severely obese, that is to say 38 BMI or Class II Obesity (Severe Obesity).

The thing that puzzles me is: Maybe I measured wrong, but I DO have thin extremities, like I have small to medium wrists for a man: 7 inches. I can wrap fingers around and do all the stuff that very thin people can do with their wrists.

And, when I get to 260 lbs, things like my collar bones stick out prominently, and I have a thin face and legs, which leads many when I get to around 260 to say that I'm "no longer fat", just a bit pudgy, and I will get comments on how I'm thin and that I can eat whatever I want and all this. It gets weird.

Bottom line is, does anybody else have mismatched measures like me. I don't lift weights or anything, and I can't claim to be "big boned" with my wrists, lol. But is it really possible I could have a lean body mass of 191 lbs?? or even 160? (which I find a more believable number). I don't rule out that I could have more muscle than I realize simply because it takes muscle to lug around this much weight.

So basically: anybody else? And, how do I stack up to others in terms of body fat percentage? I dunno normal, and it's hard to google this information.

05-21-2010, 03:53 PM
Yup! I do. According to BMI and weight, I am hugely obese and while I am definitely overweight, I get shocked looks when people find out my weight and by people I mean my doctor. I guess it's weird that someone who is 5'4" and almost 250 pounds can wear a size 16/14.

05-21-2010, 05:13 PM
I always think of BMI as being sorta like how many square yards of skin you are. Body fat is about density. You can have a very good BMI but if it's all soft fluffy fat, then you'll have a higher body fat percentage. Conversely, a super well muscled athlete can have a crappy BMI because his muscle is so heavy.

Does that make sense?

05-21-2010, 05:27 PM
Why don't you go to the gym and have your body fat tested? Much more accurate. :)

05-21-2010, 05:49 PM


Not sure if the pictures will work... (They came from here: http://www.leighpeele.com/body-fat-pictures-and-percentages )

I thought they were interesting how different two people with the same body fat % could look very different.

I think comparing BMI and fat % is like comparing apples to oranges. Beside that part where I think BMI is a crock, it is just considers height and weight. While fat % is about the make up of your body.