• image.alt
  • With Mayo Clinic nutritionists

    Jennifer Nelson, M.S., R.D. and Katherine Zeratsky, R.D.

    read biography
The Mayo Clinic Diet Book, learn more

Free

E-newsletter

Subscribe to Housecall

Our weekly general interest
e-newsletter keeps you up to date on a wide variety of health topics.

Sign up now

  • Nutrition-wise blog

  • May 8, 2010

    BMI may underestimate obesity in women

    By Jennifer Nelson, M.S., R.D. and Katherine Zeratsky, R.D.

24 comments posted

Recipes for Healthy Living

Subscribe to our Recipes for Healthy Living e-newsletter for healthy and tasty recipes.

Sign up now

Attention young ladies — you're fatter than you think.

At least, that's the conclusion of a study recently published in the journal "Obstetrics and Gynecology." The study offers evidence that body mass index (BMI) — the standard for determining whether someone is obese — may not be accurate in women between 20 and 33 years of age. In fact, BMI failed to identify nearly half of the women in the study who were obese.

BMI is calculated by taking your weight in kilograms and dividing it by your height in meters squared. This method has been used to classify overweight and obesity for decades. BMI is also used to determine weight loss strategies, including whether weight loss surgery is indicated — and whether insurance will cover it.

How did researchers uncover the BMI problem? In addition to calculating BMI scores, they used body scans to determine body fat composition. Based on BMI, 37 percent of the women were considered obese. However, the body scans revealed that 63 percent of the women were actually obese. The study's authors suggest that additional research is needed to determine more accurate BMI cutoffs for women.

So what? This means we're fatter than we thought? It also means that the obesity epidemic — at least for young women — is more serious than we thought. Many young women with obesity are erroneously being deemed "normal weight" or "overweight" and therefore aren't getting appropriate health advice. And we know that obesity increases the risk of serious health problems, such as high blood pressure, high cholesterol, type 2 diabetes and heart disease.

What's your BMI? What does it mean to you?

24 comments posted

blog index

  • February 22, 2013 12:30 a.m.

    I am a 47 y/o woman, who weighs in around 156 lbs. My BMI is 26 - that means I am OVERWEIGHT. I am fat according to the medical community. And yet... I wear size 4-6 pants, depending on brand/style, etc. Really? You have the nerve to tell me I am fat? BMI doesn't take into account my build or the amount of lean muscle vs. adipose tissue. The medical community needs reevaluate their assessments of weight is judged.

    - Rebecca

  • November 26, 2012 10:32 p.m.

    i don't need a bmi to tell me i am overweight, i know because i feel like crap, my clothes no longer fit, and its getting harder to find clothes that do fit, i only need to lose 10-15 pounds, but i know that because i know my own body, oh, and i can also look in the mirror, do away with it, its just another way to make people feel worse than they already do.

    - barb

  • June 30, 2012 9:24 a.m.

    The introduction of the only-somewhat-accurate BMI is an indication of the real problem: some of us don't know what our healthy weight is! My mum and I are similar in shape (yeah, she's doing pretty well), except she's 2" taller and her measurements are 1-2" larger. However, because of her lighter bones and slim legs (mine are muscular), she's 4 lb lighter than I am. To reiterate: she's taller and wider, yet lighter. My BMI is 22.5 and hers is 19.5. So we just look in the mirror and make sure we look right. It's not hard, you just need to be honest with yourself.

    - Andrea

  • March 24, 2012 11:48 a.m.

    Another good post by MayoClinic. BMI is a relatively straightforward equation that measures a person's body fat by comparing their weight with height. I just wanted to add the calculation to the online BMI calculator: (Weight in pounds) / (Height in inches) (Height in inches) x 703

    - BMI

  • October 13, 2011 11:16 a.m.

    The number of fat people has increased together with the number of cars on the street. Why do people who are overweight or obese want to do away with the BMI? Might as well do away with a blood pressure test when your hypertensive.

    - Sylvia

  • September 10, 2011 9:39 a.m.

    Muscle is everything. Skinny fat is still fat

    - Chris

  • July 1, 2011 6:06 p.m.

    @ Beverly... omg noooo never try and use this to tell if your child is healthy. Can your child run? Will he play outside for an hour without whinning about being tired? Is the food in your home mostly of the healthy types of snacks and meals? then your kid is fine. I hate these people trying to say that a kid is obese at the age of 2 or 3 years.. yes it can happen but that is not normal that has to be a medical issue. WIC always said my kids where over weight and now they say that about my grand kids.. but they run circles around other kids on the play ground so whos kids are healthier? rofl

    - Sheena

  • July 1, 2011 5:59 p.m.

    BMI I am sorry but it is full of BS, Why the fight to make everyone look the same skelatal way is beyond me. I can understand if I am 200 300 + and stand 5'2 but at 5'3" and even at 150 I am FAT? are you kidding. I look best at 145 or so, this BMI does not tak anything into consideration. not DNA or culture or nationality. neither of my daughters will be skinny, and they would look sickly if they were. So i think people should live at the weight they 'feel' best at and let the BMI take a DIVE.

    - Sheena

  • June 2, 2011 7:57 p.m.

    I've always wondered why, with the technology and medical advancements we've had, we still use such a generic measurement of obesity. Very simplified, weight divided by height...what about muscle? And (already said) bone density? This simplicity makes it possible to use the same measurement for men or women. We are built quite different. I agree that it is about time we do away with BMI as a basis for healthy weight.

    - Julie

  • April 27, 2011 12:37 p.m.

    I, too, found the opening line of this article insensitive.

    - Ginny

  • March 24, 2011 9:40 a.m.

    The question is, why aren't the size of bones considered? In wrestling there is an obvious difference between small-boned people and medium and large-boned people. A 107 pound woman who is 5 feet 5 inches tall will have a BMI Mass that puts them as "underweight", when in fact they are just petite (small boned). Jockeys are another type human who make the statistics false. Also, a Body Builder can be 5 feet 5 inches tall and weigh 160 pounds of dense muscle. Where does that leave the BMI "Index"? Shouldn't these things be "qualified" at the bottom of your labelling and categorizing statistics that have a one size fits all mentality? You know, you are really lacking something essential in your research and stats.

    - Mario

  • March 18, 2011 10:46 a.m.

    Even though the study is feasible the writer of this article has poor judgment - The first statement of this article is insensitive. "Attention young ladies — you're fatter than you think." Although this statement was probably intended to "catch" a reader's interest. There is no reason for such an offensive blurb.

    - Liz

  • December 20, 2010 1:47 p.m.

    Okay, I don't know why people have BMI's to be honest. This calculation can't see your physical appearance. You may have one part of your body that's Disproportionate, but you cant help it because it's hereditary. So how would it know? It shouldn't say your over or under weight. This BMI told me I'm over weight, I'm 2 points over big deal! I have a butt and boobs which is most of my body weight, which is a family trait...Well sorry to say but it's wrong I am not over weight. If your content with yourself who's or what's to tell you what you are.

    - Vickki

  • December 13, 2010 2:16 p.m.

    All over the world the obesity is on the rise and all over the world we tend to be less physically active than we need be. No it does not mean spending two hours each day in a gym. James Levine of Mayo Clinic has found that we expend more energy through Non exercising Activity Thermogenesis. Unfortnately the sedentary lifestyle is a state of the mind , not so much as simply why we don not get up and move issue. Frankly I believe that if this issue is global (wherever we have excess food and potential for INACTIVITY) we seem to move less than it's good for us. Nature has not made us so vulnerable a to sabotage our own health. Our thinking, our, our bahaviour, our culture has. Until we do not venture to understand that we are either going to feel GUILTY for being called fat, or get into physical exertion because we are scared of the looming diseases. Allow yourself to live fully, and most of your activity (and other health) problem will be gone. Yes give yourself freedom - to move, to speak and sing, to have sexual pleasure as your right, to explore and eat without guilt or counting with trepidation every calorie. Until then our weight will probably remain a issue that will only get worse.

    - Arif

  • November 16, 2010 5:14 p.m.

    It can overestimate too. BMI says I'm 10-11 pounds overweight but I run regularly and have an optimal waist to hip ratio. And no I'm not Hulk muscular (just normal muscle tone and large frame) How about we take away the BMI for good?

    - Vee

  • July 24, 2010 8:26 p.m.

    oh well one solution... just exercise :)

    - ahmad

  • June 1, 2010 2:59 p.m.

    BMI means nothing to me. For just about every physical problem I've ever had, the answer is lose weight, eat right, get more sleep, get more exercise. Right. Got the message. But the message does nothing for me. There are thousands of approaches for each of these four things. I've tried bunches of them on my own. Haven't got a clue what is right for me or how to tell helpful from harmful.

    - Susan

  • May 19, 2010 5:45 p.m.

    It is important to have your body fat measured, BMI alone is not enough of an indication. Body builders have high BMI's but low percent body fat and some people have very little muscle but high amounts of fat so they have a low BMI. Make an appointment with a Registered Dietitian to see if you are in a healthy range

    - Sierra

  • May 12, 2010 8:52 a.m.

    When I walk into a room of my peers, it appears to me that 95% of the gents are overweight or obese. It's just a visual "study", however, I think the 66% figure being touted is an underestimate.

    - Ken

  • May 12, 2010 1:25 a.m.

    I have had type 2 diabetes since Feb 07. It is well controlled with minimum medication, going to gym 3 x week, walking dog, doing pool exercises. I lost a lot of weight within the 1st year after diagnosis and have been relatively stable since. Pleased to be moved from the obese to the overweight categories. MD was blown away with how good my last test results were but then the clinic nurse who reviewed my program noted my weight was slightly up on the previous time and wanted my cholesterol to drop still further. I have been very disheartened ever since as I am 67 and losing weight seems nigh on impossible. All the harping on diabetes and weight management is a real downer.

    - Ellen

  • May 11, 2010 12:51 p.m.

    Great info on BMI. Is it appropriate to use BMI for assessing obese children?

    - Beverley

  • May 11, 2010 12:31 p.m.

    Calculating the BMI is a horrible way to figure out if you are overweight or obese. My doctor said by looking at the numbers I was obese, and asked if I get regular exercise. I went and did the bodpod which is way more acurate and I was in the healthy category. I would hope so considering I am running my second marathon in two months! The numbers don't account for muscle and bone density.

    - Jen

  • May 9, 2010 3:39 p.m.

    Here's the reference: Mahbubur Rahman, MD, PhD, and Abbey B. Berenson, MD, MMS Accuracy of Current Body Mass Index Obesity Classification for White, Black, and Hispanic Reproductive-Age Women OBSTETRICS & GYNECOLOGY VOL. 115, NO. 5, MAY 2010

    - Lynn

  • May 9, 2010 2:17 p.m.

    It would be very helpful if you included the name of the leading author and reference information for a research article. I often want to find the original article and it takes a lot more effort without this information. Besides those scientists worked hard on that project and deserve a little name recognition :)

    - Lynn

Post a comment
  • Print

  • Share on:

  • Email

Advertisement


Text Size: smaller largerlarger