We Are Fatter Than We Think We Are

An African-American friend of mine on Facebook recently jubilantly posted a link to this article about a recently-discovered problem with the BMI Index, a number widely used to determine body fat levels — whether people are underweight, healthy, overweight, or obese.

The BMI index was calculated with reference to caucasian body types. But people from different ethnic backgrounds have bodies that might be constructed slightly differently, so one BMI might not accurately determine everyone’s body fat level. A more direct measure of body fat can be found through Dual X-Ray Absorptiometry (DXA or DEXA), which measures body fat directly, rather than as an index. Here are the basics:

BMI is a formula that estimates a person’s body fat using only his/her weight and height. The result is then used to determine weight categories: 18.5 and below is considered underweight; 18.6 – 24.9 healthy; 25 – 29 overweight and 30+ obese.

“This scale was created years ago and is based on Caucasian men and women,” says Bray, “It doesn’t take into account differences in body composition between genders, race/ethnicity groups, and across the lifespan.” (link)

The good news for African Americans and bad news for Asian Indians is after the jump:

When the two results were compared, researchers found that the DXA estimate of percent fat of African American women was 1.76 percent lower for the same BMI compared to non-Hispanic white women. Since BMI is assumed to represent body fatness, an African American woman would not be considered overweight or obese until she reached a higher number than what is indicated by the current BMI standards. The opposite is the case for Hispanic, Asian and Asian-Indian woman. Their percent fat is higher by 1.65 percent, 2.65 percent and 5.98 percent, respectively. So they would be considered overweight or obese at amounts lower than what the BMI standards indicates. The results for men were similar.

In short, people who are ethnically “Asian Indian” (desi, South Asian, etc.) are on average approximately six percent more overweight than they previously might have thought.

Of course, I’m sure the study, published in the British Journal of Nutrition, probably isn’t flawless, though I don’t know the precise details of how the study was conducted. One does wonder how they’re defining “Hispanic,” since the term Hispanic refers to language rather than race/ethnicity. I also wonder whether different sub-communities within the Indian subcontinent might end up having different average body fat levels relative to BMI. (Punjabis, for instance, are often thought of as on the heavier side by comparison to other Indian ethno-linguistic groups.)

This isn’t a post designed to make everyone feel fat, though I realize it might have that effect. Rather, the point is to raise awareness about the health risks associated with obesity: South Asians are more likely to have those sorts of problems (diabetes, heart problems, and the like), so we might have more of a collective investment in focusing on that aspect of our health.

40 thoughts on “We Are Fatter Than We Think We Are

  1. The DXA wikipedia page states that this method is not a reliable way of measuring fat content. That confuses me on what to make of the results of this study.

    However, it has been suggested that, while being very accurate to measure minerals, it is very unreliable in measuring fat content – this was never its original purpose

    As per BMI i am not fat. I guess i will just stick to that system for now!

  2. “However, it has been suggested that, while being very accurate to measure minerals, it is very unreliable in measuring fat content – this was never its original purpose”

    Yikes, I hadn’t seen that. I wonder if that issue is addressed in the study itself. I guess, since they seem to have worked with large pools of people, and focused on getting average body fat levels using DXA, it might cancel out the possible problems associated with the method. On the other hand, if the method is really completely unreliable, then the whole thing has to go out the window.

    I will see if I can get access to the study itself through my university library, and maybe add a little more.

  3. For anyone interested, below are a few paragraphs from the study itself. The authors seem confident in using the DXA machine to measure body fat, and cite an essay by Lohman and Chen on using DXA for this purpose. I do not know enough about the science to say who is right….

    “Subjects were recruited from the Training Intervention and Genetics of Exercise Response (TIGER) study. The TIGER subjects were students enrolled at the University of Houston (Houston, TX, USA). The target subject was a sedentary individual under the age of 35 years who exercised less than 30 min/week for the previous 6 months, and was not actively limiting energy intake by dietary modification. Subjects were excluded from the study if they had a physical or physiological contraindication to aerobic exercise, a known metabolic disorder that may alter body composition, or were pregnant or lactating.”

    “The TIGER study subjects engaged in 30 weeks (two semesters) of exercise training, 3 d/week for 30 min/d at 65–85 % of heart rate-defined VO2max. The data came from five yearly cohorts. The sample consisted of 806 females and 509 males who ranged in age from 17 to 35 years. These data included men and women who had from one to three measurement visits over the 9-month study duration. The measurement visits were at baseline, after 15 weeks, and at the end of the 30-week exercise programme. The total number of observations for the visits was 1300 for women and 820 for men. The race/ethnic group composition of the male and female samples differed slightly. The composition of the 509 men at baseline was: NHW, 37 %; Hispanic, 26 %; AA, 22 %; Asian Indian, 5 %; Asian, 10 %. The composition of the 806 women at baseline was: NHW, 29 %; Hispanic, 25 %; AA, 35 %; Asian-Indian, 3 %; Asian, 8 %.”

    “Height was determined with a stadiometer (SECA Road Rod; SECA, Hanover, MD, USA) and weight was measured with a digital scale (SECA 770). Subjects reported their birth date, sex and race/ethnicity using a standard, coded self-report demographic form. DXA was used to measure BF%. The DXA data for the first two cohorts were only measured at baseline and 30-week time points. DXA data were available for all three test visits for cohorts 3 to 5 if the subject completed the exercise programme. All individuals had baseline data. The number of individuals who had repeat tests were: 15 weeks, 311 women and 217 men; 30 weeks, 183 women and ninety-four men.”

    “Whole-body DXA scans were completed on a Hologic Delphi-A unit (adult whole body software v. 11.2; Hologic, Inc., Bedford, MA, USA) and a Hologic Discovery W instrument (adult whole body software QDR v. 12.3). The same trained technicians administered the DXA scans. The instruments were calibrated daily with a spine standard and weekly with a step calibrator, as described by the manufacturer. All female participants completed a standard urine pregnancy test before DXA testing to ensure that they were not pregnant before scanning. Subjects were asked to lie in the supine position and remain still. The entire scan was completed in less than 6 min. Software supplied from the manufacturer was used to calculate whole-body (minus the head) fat mass, lean mass and bone mineral mass. Total DXA weight was computed by summing the DXA parts and used to compute DXA-BF%. As recommended by Lohman & Chen(20), DXA weight and scale-measured body weight were compared with linear regression. The R2 between measured and DXA weight was >0·99. The slope of the measured–DXA weight regression line of 1·01 (95 % CI 1·00, 1·02) and the intercept of − 0·08 (95 % CI − 0·37, 0·20) were within chance variation of 1·0 and 0. The standard error of the estimate for scale-measured weight was 1·5 kg.”

  4. The Jalebi Liberation Front (JLF) thanks Almighty God for punishing opressors of Jalebi nation. The repression, persecution, plundering, and eating of Jalebis by South Asian opressors has finally been answered.

    We ask Almighty God to grant us victory on our enemy, give tham Tummy Ache, Auntie Butt, Sari Rolls, and Uncle Stomach, and defeat them.

  5. ROTFL @ JFL @6.

    I can be your poster child as a victim of the JLF as now I possess all three characteristics of the oppressors. Unfortunately, as all members of cults would attest, I have also become an oppressor myself, inflicting jalebis, pakoras, and vadas on my hapless cohabitants. Now, I have seen the light.. Jai JLF!

  6. Waaaait, haven’t you heard? BMI is out, waist-hip ratio and waist circumference are in. Belly fat is more predictive of mortality and cardiovascular risk factors than BMI is. I.e., cut the beer gut.

  7. Once I figured that Mike Tyson at his peak (210lb, 5’10″) was obese according to the BMI , I stopped paying attention to it. If you worked out, it pushed you upwards on the obesity scale as the muscle mass increases.

  8. I am a typical indian. 5′ 6″ and 173lbs nekkid [4lbs of dong and 6 lbs of body hair]. i used to think i am svelte. now i am just depressed. must. eat. jalebi.

  9. I am a black man in his early 30s. When I was 200 pounds a few years ago (6 feet tall), I was considered overweight and would have had to drop 15-20 pounds to be in the normal range. This is a little ridiculous, though, since I never looked overweight by any means. People had a hard time accepting that I weighed that much. My girlfriend pointed out to me that it didn’t take into account my black physiology, and I suspect that this is true. I have since lost 25 pounds (not voluntarily) and look quite skinny, but the BMI says that I am normal. Unlikely.

  10. Punjabis, for instance, are often thought of as on the heavier side by comparison to other Indian ethno-linguistic groups

    as always, bobby jindal leads the way. vat a man! vat a man!

  11. Once I figured that Mike Tyson at his peak (210lb, 5’10″) was obese according to the BMI , I stopped paying attention to it. If you worked out, it pushed you upwards on the obesity scale as the muscle mass increases.

    tyson’s an outlier in boxing, with his short stature coupled with a lot of muscle mass. most boxers, even with their muscle mass, fall within an acceptable bmi range…like take roy jones at 5-11 and 173 (started out in the 150′s) or oscar de lahoya at 5-10 and 150 (started out in the 130′s), who weighs less than khoofi…but that could be attributed to dong.

  12. Curious and wondering: Is this because Indians on average have a lower muscle to fat ratio and less muscle in general than African-Americans? (speculation, I don’t know if this is true or not)

    Are there any the positive aspects to the physiology of South Asians?

    As for the BMI, I don’t pay attention to it. It doesn’t really apply for people who work out, and are into resistance training. I’m 6’2″ / 190 lbs, and trying to get 10-20 lbs bigger, which is extremely hard because I’m a hard gainer (blame my indian genes for that :P ).

  13. Show us a picture deemz! show us!* Ahem…I mean an example so we can fully understand…um, you know, your point. Strictly scientific of course.

  14. Are there any the positive aspects to the physiology of South Asians?

    you know when they say, he ‘won by a nose’… desis have a natural advantage. heck, desis can even win by the nose hair.

    p.s. i think bobby jindal’s juiced on altoids.

  15. Are there any the positive aspects to the physiology of South Asians?

    the elongation allows for the desi nose to capture more moisture in dry weather typically found in the hilly regions around the hindukhush.

  16. Westerners are way too obsessed about weight. I mean, some doctor went on TV stating that Jordan Sparks was a bad role model for youth because she is “obese” and is sending out the wrong message!

    Obese? The girl is “healthy” i.e. good-n-chubby (curvaceous), for goodness sake!

    I suppose that “doctor” would say Paris Hilton is a good role model because she’s a stick.

  17. I think a person who is 5’10″ and 240 pounds of fat is just as unhealthy as a person who is 5’10″ and 240 pounds of muscle. It is still strain on your heart, tendons, ligaments and digestive system to be eating that much.

    Any Indian can tell you that Indians naturally have more fat on their bodies than a white person. Even skinny Indians have that “Look im not fat” look with their cloths on, but take off their shirt and it’s like “Where did you get those boobs(for guys) and love handles from?”

  18. I am a typical indian. 5′ 6″ and 173lbs nekkid [4lbs of dong and 6 lbs of body hair]. i used to think i am svelte. now i am just depressed. must. eat. jalebi.

    4 lbs of dong?

    Meaning?

  19. 4 lbs of dong?

    i was being silly, Sepiaaah. it was a reference to the pachydermal pundjabee proboscis. please pardon the poke.

  20. there is an interethnic difference. see here and connect he dots. my BMI is lower than the average in the USA, but i assume it is the average for what i “should” be. caear’s wife should be above suspicion and all that….

  21. 4 lbs of dong?
    i was being silly, Sepiaaah. it was a reference to the pachydermal pundjabee proboscis. please pardon the poke.

    Hmmmmmm… I’m thirsting for a textural experience right now….

  22. “One does wonder how they’re defining “Hispanic,” since the term Hispanic refers to language rather than race/ethnicity.”

    Not this again… Basically they probably used a sample of mostly Mexican-Americans, probably mostly mestizo (mixed white/indigenous) and slapped the Hispanic label on it. Caribbean Hispanics, who are mainly some mix of white/black, should generally just ignore any medical study that talks about results for Hispanics.

    The medical field is HELL-BENT on making Hispanics seem like a distinct race by just getting a big sample size, which will generally be mostly Mexican-Americans in the U.S., and calling it scientific. It’s the only scientific field that is still trying to pull this off.

  23. The medical field is HELL-BENT on making Hispanics seem like a distinct race

    Well, native Indians of the Americas are a distinct ethnography and the “hispanics” or “latinos” of the Americas are descendents (often mixed) of those Indians, just like persons of African descent are a distinct ethnography.

    We know that various ethnic groups have different health issues. For the sake of science and human health, why not try and research these things according to ethnographical groups?

  24. To put this in some context, the BMI system is already very flawed. It’s kind of nice to see that they’re trying to make it more inclusive but, frankly, I still think whatever they come up with will have questionable value for determining health :/

  25. sorry radhika

    Wasn’t directed at you, khoofia, but it’s cool. The general idea that somehow a person is “fatter” or “skinnier” than they think they are in a culture that has so many issues when it comes to body image isn’t healthy, imo. That’s what I was getting at. :)

  26. The problem with the BMI is that it’s a statistical figure. It’s meant to assess the average trend for a large sample of people. Trying to attribute the BMI derived from averages to individuals doesn’t work as anything but a very rough guideline.

  27. The basic problem with the BMI is that it imposes a 2-dimensional constraint while humans are three-dimensional. It needs to be a constant x height cubed instead of squared.

    The scale may work fine for a range between 5-6 feet but it breaks down badly at the high end. Going by BMI practically every NBA player is obese.

  28. @khoofi

    Aw but the elongnation of the “desi” nose is just of the Pakistanis! Indians usually have short, small snubby noses. :(

  29. ^ Hey, that’s the second post in the past day implying pakis have big ugly noses and indians have small ones! and I have to say, I don’t see it. I mean, sure punabis are known for the desi schnoz but there’s like millions of them on your side of the border too :P

    • I think you guys got the big noses from the Pathans (like the Khans of BW) rather than Punjus, lol. ;p “Pathani naak,” etc. I live in Delhi and know lotta Punjabis and most of them have tiny, button noses. Non-Punjabi Indians stereotype that Punjabis have long, prominent ones, but most don’t seem to have one, so I never got that stereotype. LOL, But what’s wrong with Pakistanis having big noses? I mean, I’m pretty sure that desis probably prefer SRK’s nose over pre-plastic surgery Shilpa’s one. I think extended rule from Middle-easterners for a long time must have had an effect for beauty standards…

  30. I found a study a while back dealing with similar issue to this post, but it was done on Indians in India, I’ll try to find and post it.