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French Scientists Link Higher BMI with Lower IQ

Xemu writes "French scientists have linked obesity to lower IQ reports the Telegraph. In a new five-year study of more than 2,200 adults, people with a low body mass index (BMI) could recall 30% more words in a vocabulary test than those who were obese. The fatter subjects also showed a higher rate of cognitive decline when they were retested five years later. In the United States, 30% of the population is obese according to OECD. That's the highest rate of obesity anywhere. Do these high obesity rates affect the average IQ of the population?" (Of course, this sidesteps discussion of whether IQ tests measure anything significant at all.)

37 of 728 comments (clear)

  1. BMI is not accurate by Harmonious+Botch · · Score: 4, Interesting

    The Body Mass Index is not accurate. It is basically mass vs height, and makes no distinction between fat and muscle, both of which increase mass measurements.

    During the rainy season, I don't exersize, so I lose muscle mass and get skinny, and I look - pardon me for saying it - like a geek. And my BMI is normal ( and allegedly healthy ). But during the other ten months, I am more muscular ( and probably a lot healthier ) and yet I am technically obese, according to the BMI.

    Do I feel smarter? Heck, I'm a slashdotter - I think I'm smart all the time.

    1. Re:BMI is not accurate by gEvil+(beta) · · Score: 4, Funny

      ...but for some reason, I'm unusually dense.

      Yes, we've noticed. : p

      (sorry, couldn't let that one slip by)

      --
      This guy's the limit!
    2. Re:BMI is not accurate by sumdumass · · Score: 5, Interesting

      Could this study just be another chicken and egg concept and we havn't discussed wich came first?

      You mentioned when you are slimmer your less occupied with food and such. Your brain is noticibly performing better as you can notice the differences. It apears though that this study is gearded towards saying slim people are just smarter or have the ability to be smarter easier then fatter people. As if fat content in a prsons body directly reflect thier mental abilities.

      Now, What if the slimmer people have traditionaly concentrated on more mental work and less physicle work, therby training thier brain instead of thier muscles. Would this mean that a person who is slimmer is smarter because they are slimmer and less occupied with food or that they have traditionaly used thier brain more and remembering things or solving puzzles becomes more easy to them. Therefore a person with a larger build, spends more time not using thier brain and more on thier muscles, watching TV, or whatever else and thier ability to perform as well as the slim person is diminished?

      I remeber in third grade when we started multiplication. I used flash cards and could do almost any problem in my head that involved less then two numbers of two digits or less (20x7). After using calculators for a while, I could do this anymore. But I have been able to return to it becauseof vaious jobs ove rthe decades. (like roofing, framing and general construction working wich involves alot of math)

      So, from my personal experience, Could it be just how a slim person spends his time verses how a fatter person might? Obviously anyone who plays sports is going to be better then anyone who doesn't. And people playing for severla years will have somewhat of an advantage over those playing for a few weeks. Is this just the reverse were the game is a mind game instead of football? And someone with several years experience because of lifestyle differences will have an advantage over someone who doesn't exercise thier mind? Could it be that slim or fat is just a reflection of how a person spends thier time and has nothing or little to do with thier fat content outside what a fat person does compared to a skinny person.

      I would like to see this studdy done again and the occupations of the people be part of it. I would bet some one of larger BMI who does something like programing or construction were he reads blueprints, sets grades, or transferes scale to live building projects might do a little better then someone who is just fat and works at wopper floppers of america. But if the burger king employee of the month does the same as one of the others of same BMI, I would conceed that fat might have an impact.

  2. BMI = Worthless by Smidge204 · · Score: 5, Insightful

    (Of course, this sidesteps discussion of whether IQ tests measure anything significant at all.)

    This also seems to sidestep discussion of whether BMI measures anything significant at all.
    =Smidge=

    1. Re:BMI = Worthless by Keebler71 · · Score: 4, Interesting
      (Of course, this sidesteps discussion of whether IQ tests measure anything significant at all.)

      Concur but I have a different take on this wording. Of course IQ tests measure something significant. The question may be whether or not "IQ tests are a signigicant measure of anything at all". My wife is an elementry teacher and we recently discussed how children are placed into gifted classes. She said that they used to do IQ testing but that has fallen out of vogue due to their being a rather politically incorrect measure (not to mention all the other types of "intelligence" (emotional, creative, et crappra)). This is sad. IQ tests are a near-perfect indicator of intelligence. That is they have a very low incidence of Type I (false positive) error. The cultural biases come into play and lead to false negatives (Type II errors). It seems the logical approach would be to use a combination of tests or qualitative assessments rather than ditching a good but non-perfect test.

      --
      "It takes considerable knowledge just to realize the extent of your own ignorance." - Thomas Sowell
    2. Re:BMI = Worthless by griffjon · · Score: 5, Insightful

      All of this conveniently ignores that correlation is not causation. maybe being stupid correlates with not taking care of yourself? Maybe they're both caused by a third variable (perhaps watching too much TV?)

      --
      Returned Peace Corps IT Volunteer
    3. Re:BMI = Worthless by rjstanford · · Score: 5, Insightful

      I used to be in the "BMI == Worthless" camp myself. Had all sorts of reasons why it was bunk, used to be able to quote muscle density, et cetera, just like everyone else on here.

      Then I grew up and lost over 80 pounds.

      Anyone who show as "obese" on the BMI charts but has enough muscle to throw things off is obviously either way toned, or way strong. Seriously. If you're an average person, even a once or twice a week gym habit, and you show as obese... then you're 99% probably fat. Grow up and admit it. Especially in the USA, "normal," is a long way from "fit." The vast, vast majority of people with high BMIs are fat, end of story.

      Sure, Tom Cruise is the poster child for "overweight by BMI standards." He's obviously not. If you can see your sculpted abs, you probably aren't as well. Otherwise, you are. Deal with it.

      If you want to ignore it, that's your decision. Be overweight. But stop pretending you're not. And also, more to the point, stop trying to convince everybody else that they're not overweight because you can't deal with your own issues. And yes, that is a more generic rant than just one aimed at the parent poster, but its still true.

      --
      You're special forces then? That's great! I just love your olympics!
  3. IQ Tests by stevemm81 · · Score: 5, Informative
    (Of course, this sidesteps discussion of whether IQ tests measure anything significant at all.)


    This wasn't a general purpose IQ test. It was a specific test of people's ability to recall words. They're talking about memory in particular, not some fuzzy idea of general intelligence.
    1. Re:IQ Tests by nizo · · Score: 5, Funny

      I bet the test was unfair; they should have asked the people who did poorly if they could, say, remember the items from a McDonald's menu. Now who has a better memory skinny boy!

    2. Re:IQ Tests by Garse+Janacek · · Score: 5, Insightful

      We damn well do know that people with high IQ are usually more successful than those with low IQ.

      True, but (as shouldn't even have to be pointed out in this discussion) correlation does not imply causation. Specifically: when people are given better education, their IQ increases. IQ is decidedly not (as you claim) "mostly in-born [and] inheritable" unless you really believe that there is a measurable sense in which whites are inherently (on average) intellectually superior to blacks and hispanics in the United States.

      Now, even aside from any issues of political correctness, I hope you aren't in fact claiming that, because it's been pretty thoroughly refuted. If you take someone (of any race) out of poverty and give them a good education, their average IQ increases dramatically. While in any group (including those in poverty) there will be certain extraordinary individuals who have a high IQ (or whatever positive attribute you're measuring) despite all disadvantages, the frequency of these individuals goes up an awful lot if you take away the disadvantages in the first place.

      The reason some people dislike IQ, or claim it does not measure anything useful, is that most discussions about it implicitly assume that it succeeds in its goal of measuring intellectual capacity independently of cultural and educational factors. In this it fails completely. Which doesn't mean that it isn't measuring anything useful, but your comment shows there are still plenty of people who think IQ is some sort of "in-born" attribute. It's not.

      There is a sort of unfairness that goes against Western ideals. The idea that anybody can pull themself up out of poverty, that every child has a chance to succeed intellectually, is threatened by this.

      I'm actually kind of with you on this. I don't think the world is as fair as a lot of people would like to believe, and I don't think that anyone can pull themselves out of poverty, everyone has a chance to succeed, etc. -- and even though I think IQ is (mostly) bunk, I think some amount of intelligence is inborn. But nowhere near all. Even people who could have been very successful intellectually can fail because of their surroundings. All of which suggests, to me anyway, that it is important to do what we can to help others out of poverty and to provide children with good educations, since they may not be able to attain these things themselves regardless of their actions (that is, unlike some Americans, I don't see poverty as a moral failing).

      But, as I said, the fact that the world isn't fair doesn't mean it's unfair in the particular way you suggest, that is, that IQ is an innate property transcending culture, language, and education, and rich folks just happen to be innately the smartest.

      --

      I am the man with no sig!

  4. Re:Timothy has low IQ? by malsdavis · · Score: 5, Insightful

    Indeed, Timothy does oversimplify the matter.

    It is slightly beside the point though because the study noticed a drop in 'cognitive function' in obese people, not IQ. Cognitive function most certainly is significant, albeit specifically to the function measured (which in this case was primarily arthmimetic and vocabulary). It was only the reporting newspaper which introduced IQ, probably for the benefit of dumber/fatter readers.

  5. This story is riddled with nonsense by RsG · · Score: 5, Insightful

    Not the study, but rather the first linked article.

    First, they make the classic error of attributing causation when the study found correlation. If that was in the original study, then I'd question the researcher's methodology, but I suspect the blame lies with whoever wrote the article. Testing people's intelligence and comparing their weight does not show a causitive link between wieght and intellect. It could just as easily show that poor judgement translates into bad eating habits and low IQ.

    Second, the criticism they reported came from a politician who tried to use anecdotal evidence to debunk the link. That's right, she said she knew witless skinny people and clever fat people, so the study must therefor be wrong. Someone ought to tell her that the plural of "anecdote" is not "evidence".

    --
    Erotic is when you use a feather. Exotic is when you use the whole chicken.
  6. Re:IQ means nothing... by kfg · · Score: 5, Funny

    Yes I have a weight problem but I don't blame it on IQ, I blame it on american diet and adverting on TV and in magazines.

    Which you aren't smart enough to ignore.

    KFG

  7. Link with poverty by Dr.+Spork · · Score: 5, Insightful

    In most industrialized countries and especially in the US, obesity is strongly correlated with low income. Since there is also a strong link between low income and low IQ scores, there may be no causal relationship at all between obesity and a lowered IQ.

  8. What Words? by malvidin · · Score: 5, Funny

    How much do you want to bet that the words weren't types of food?

  9. Re:frist psot by Pflipp · · Score: 5, Funny

    wow, you must be fat!!

    --
    "We can confirm that Debian does *not* ship the version with the trojan horse. Our version predates it." [CA-2002-28]
  10. Fat and Stupid? by Ranger · · Score: 5, Funny

    The French are calling us fat, lazy, and now stupid. Great, well at least we aren't a bunch cheese eating surrender monkeys. Time to eat some more pork rinds and watch American Idol. I hope I don't have to get out of my chair to find my remote. Found it. It was under a fold of fat. I also found my car keys.

    --
    "You'll get nothing, and you'll like it!"
  11. Re:IQ means nothing... by NosTROLLdamus · · Score: 5, Insightful
    My IQ is only 100 but I am a lot smarter than most people for my 'low' IQ.

    Sorry, fatty, but everybody thinks they're smarter than everyone else. Everbody. It's okay though, you can take solace in the fact that everyone has the same lame excuses for their short comings.

  12. Re:Jokes! by sTalking_Goat · · Score: 4, Insightful

    Yeah, what no one bothers to go into is that the Americans tried pencils, but realized that broken pencil points would float away and get into everything, possibly harming delicate electronics...

    --

    My days of not taking you seriously are certainly coming to a middle...

  13. one thing to think about... by AxemRed · · Score: 5, Insightful

    There are probably other factors involved here. For example, poverty has also been linked to obesity (in America.) And less intelligence can also be linked to poverty.

    So does obesity somehow lead to mental decline? Or are people who are less intelligent more likely to let their physical health deteriorate?
    Or maybe less intelligence leads to poverty which leads to obesity. Then again, it could be the other way around...

    Correlation does not equal causation. If I had to place a bet, I would say that the link between obesity and intelligence isn't biological like the article is inferring. There may be some kind of link there, but I bet that other factors are more influential.

    1. Re:one thing to think about... by malsdavis · · Score: 4, Insightful

      "Correlation does not equal causation. [...] There may be some kind of link there, but I bet that other factors are more influential." yada yada yada, I think I know everything!

      I can't stand posts like this. You obviously have not read the academic report and therefor your conclusion about its fallacy are completely worthless. I have not read the actual report either but to hear you make an instant "it's probably due to this other factor" summary about something you have obviously not even read is infuriating!

      The primary task of academic studies is to identify the true reason for an observed correlation. Every researcher knows that "Correlation does not equal causation" and the fact that the report has been published in a respected journal means for definate that the researchers have taken steps to ensure other obvious factors - like the ones you mention - are accounted for.

  14. Re:Timothy has low IQ? by Golias · · Score: 4, Funny

    There are decades of data to prove the corellation between IQ and actual, demonstrated intelligence and success in the real world. Maybe you would like to clarify yourself, Timothy?

    The disproportionately high representation in groups like MENSA of lonely singles who earn below average salaries in unsatisfying jobs seems to counter your "decades of data" (which I have never seen.)

    Or are you defining "demonstrated intelligence" as the ability to recite Star Trek dialog by rote and "success in the real world" as having your very own crafts store at the local Renaissance Festival?

    --

    Information wants to be anthropomorphized.

  15. IQ means nothing, MENSA is pointless and so on by BeeBeard · · Score: 5, Funny

    You're right, IQ is incredibly meaningless. A well-socialized individual with a good work ethic, who is willing to parlay whatever gray matter they have into the task at hand will always prove successful at life. Many of the under-20 uber-nerds who cling to their IQ scores as proof positive of their superiority over others haven't figured this out yet, and to their credit, it's something that's only realized with time: Intelligence is both nature and nurture--the daughter of a doctor and lawyer becomes a bum if she has no direction or commitment. The daughter of a field hand and a grocer becomes the world's most well-respected biologist if she has direction and commitment.

    -------------

    Funny story: The guy downstairs had his "MENSA Bulletin" delivered to my mailbox by mistake (probably due to the innerwebs and lack of blue mailboxes!), so of course I kept it. I've been leaving it prominently near the john for some high brow bathroom reading. And man oh man, have I been disappointed. The articles are poorly conceived and written, the letters from readers absolutely dumb. The pictures of "smart people" show them not even badly dressed, but incapably dressed--as in , for example, they clearly missed belt loops when they were putting on their belts (Is looking accidentally slovenly for nationally distributed photographs the mark of a genuinely intelligent person who likes themselves? I submit that it is not.)

    So my friends have been coming over, and when they inevitably have to use the restroom, they see the magazine and go "You're in MENSA?" all accusingly. And of course I pretend to be, and mutter something about how "we're trying to reform the government under our own intelligent rule" (did you see that episode of The Simpsons too?)

    And as I can feel their opinion of me lessening, lessening...I finally let on that, no, of course I'm not a part of fucking MENSA. And every time, they respond with something like "Oh I was gonna say, because those people are idiots!" And then we page through the magazine together, mocking it the entire time. And we live happily ever after. The end.

  16. Perhaps... by OpenSourced · · Score: 4, Funny

    people with a low body mass index (BMI) could recall 30% more words in a vocabulary test than those who were obese

    Then perhaps people get fat because they can't remember they have already eaten.

    --
    Rome taught me patience and assiduous application to detail. Virtues which temper the boldness of great, general views.
  17. Of course IQ measures something... by Morosoph · · Score: 4, Funny

    Specifically, IQ measures how slim you are!

  18. Memory != IQ by mkiwi · · Score: 4, Informative
    It is common in society to associate people with good memories as people with high IQ's.


    This is simply not true. If you actually take an IQ test, you will see that it does not test your memory as had been done in the study, but rather your cognitive thinking skills. In fact, there are many people who can memorize history or math equations or whatever, but they come up far short when they have to apply the concepts they memorized.

    Again, memorization is not critical thinking, and memorization != IQ.

  19. A truly groan-worthy pun... by InfinityMinusOne · · Score: 4, Informative

    to someone speaking dutch. (for the non-dutch, 'slim' means smart in dutch)

  20. Find a shady place to sit by BeeBeard · · Score: 5, Insightful

    For starters, let me disabuse you of the notion that I spend my evenings looking through the dirt-stained glass of an abandoned feed factory, breath frosting up the glass, spying on the secret meetings of the local MENSA chapter and hoping against hope that this week--oh god let it be this week--will be my chance to finally get admitted.

    I actually have received invitations to attend MENSA meetings in the past, but have always declined. (Is that how recruitment is done? God only knows.) I politely say that I have a "differing philosophy". Namely, I believe that intelligence and success should be measured in terms of real, humanistic achievement in the real world, and not by corny metrics that determine whether or not a person should be admitted to a shamelessly self-promotional smarty-pants club. But of course I don't say all that. Politely declining the invitation is really enough.

    I know that must just fry you--that there are people out there in the world who are at least reasonably smart and reasonably socialized, and who look at their introverted and prideful intelligent brothers with pity. It may seem at odds with what I read as teenage angst, but I assure you we exist.

    And speaking of teenage angst, you might want to stop using the lexicon of a teenager. "Jocks"..."frat guys"...it's the language of someone who still thinks of people in terms of symbolic high school lunch tables (i.e. somebody not all that smart after all). If you're just some silly immature kid (I understand that about half of Slashdot readers fit that description)--then you get a free pass, because that's all you've seen so far in terms of how people organize themselves. But if not, then, well, there's that whole pity thing again. To phrase this in terms you've voluntarily adopted, I am no jock, or frat-guy, or anything else. I sit at everyone's lunch table, and I don't use their interests as some kind of bogus reason to judge and dismiss them.

    So I guess to be more crass about things, that, my boy, is why I haven't joined your fruity little club.

    Good luck--may your false pride and wanton disdain for others take you to great new heights.

  21. Re:IQ means nothing... by Columcille · · Score: 4, Funny

    But some of those people are actually right. Take me for example - I'm smarter than pretty much anyone else out there. I even figured that fact out on my own! The fact that everyone else disagrees with my conclusion just proves how ignorant they all really are.

    --
    I love my sig.
  22. Mensa bashing by Andy+Social · · Score: 4, Funny

    Hey! I'm a Mensa member and ... Oh, never mind, it's acutely accurate. *sigh*

    --
    Illegitimi non carborundum
  23. Re:Timothy has low IQ? by killjoe · · Score: 5, Interesting

    My father by most peoples definition is brilliant. He is a scientist, he speaks several languages, he is a published author of several highly regarded books both fiction and nonfiction.

    Despite all this intelligence he refused to take care of himself, got obese, had several heart attacks and then a series of massive strokes. For decades his doctors told him to lose weight, to stop eating junk food, to drink more water, to exersize and he ignored not only his doctors but his family and friends too.

    Now he can barely talk, his mobility is severly limited, he has problems reading and all he does is watch tv.

    Was my dad smart or dumb? I used to think he was brilliant but now I realize that he was dumb. Too dumb to prioritize, to take care of the important things in life. The time he took to learn that one more language or to write that one more book should have been spent taking walks or something.

    I know lots of "smart" people who are actually dumb like that.

    --
    evil is as evil does
  24. Mutual Admiration by rumblin'rabbit · · Score: 4, Insightful
    No kidding. Probably few people who are truly intelligent want much to do with a mutual admiration society for people who do well on tests. They prefer the company of people who accomplish things.


    And I'm not just saying that cause I was rejected. No, really.

    1. Re:Mutual Admiration by rumblin'rabbit · · Score: 4, Funny

      Witty losers, you say?

      Have I got a web site for you!

  25. Re:BMI is a poor way to measure body fat. by benzapp · · Score: 4, Informative

    It's Body Mass Index, not Body Fat Index.

    All the BMI measures is your risk for a variety of heart related ailments. The theory is that the more massive you are, the harder your heart has to work.

    The issue is most people lack the ability, the financial resources, and the discipline to gain an extraordinary amount of muscle mass. So, in the vast majority of cases, the BMI does measure body fat. But, it has nothing to do with the percentage of your body that is fat or how toned you are.

    Just thought I would add that to what you are saying.

    --
    I don't read or respond to AC posts
  26. There certainly is a definition of "intelligence" by mbkennel · · Score: 4, Interesting

    I know of no comprehensive definition of intelligence that is agreed upon by a majority of scientists, but if you have evidence to the contrary feel free to provide it. Obviously, there isn't going to be any scientific definition of "success in the real world".

    This is not true.

    There certainly is a pretty well established definition of general intelligence 'g' used
    in psychometric studies which has, contrary to what some people may desire, withstood many
    challenges, and is logically and empirically consistent.

    Essentially: you have a test of a multitude of widely varying tasks all of which are at some level, obviously "mental", and you measure the performance of people on all these varying axes.

    Intelligence is the projection along the first principal component, reflecting the fact that people who do well on some of them, tend to do well, up to some degree, on most of the other ones.

    This is a highly consistent phenomenon among all human groups tested.

    It is correlated with numerous, objective, biological measurements in prospective, controlled experiments.

    This is also a falsifiable hypothesis as well, as for example, performance on a number of
    *other* tasks, most of which are probably less mental, significantly less
    correlated with 'g', except probably among the very lowest tail which reflect significant disease or genetic disabilities with systemic effects.

    Obviously, there isn't going to be any scientific definition of "success in the real world".

    No not in a comprehensive sense but you can definitely come up with specific proxies which approximate it, and quantify it fairly well. For example, 'felony imprisonment' is clearly 'not successful' by almost everybody's standards.

  27. study doesn't say anything about "obese" people by chartreuse0 · · Score: 4, Informative
    I went back and read the actual paper upon which this article is based, and the summary given on Slashdot is rather inaccurate. This article does not claim to compare "normal" weights to "obese" weights. Rather, it purports to show a trend primarily within the normal range of BMI.

    In particular, they broke up BMI's into five groups: (1) 15-21.5, (2) 21.5-23.4, (3) 23.4-25.2, (4) 25.2-27.7, and (5) 27.7-45, where BMI's up to 25 are considered normal, up to 30 are considered overweight, and over 30 are considered obese. Even within the final group, not all the participants are obese.

    It begs the question of why they didn't compare "normal" weight IQ's to "obese" weight IQ's, as this would be a big story and a more impressive research finding! It's likely that either they didn't have enough obese participants to satisfy statistical significance (so most of group (5) is actually individuals with BMI's of 27.7 to 30), or they didn't find that obese people had lower IQ's. When the BMI groups that they break up their data into as strange as this, and not at all the groups that are normally used in research papers, it begs the question of what kind of data massaging they had to do to find their conclusions. Did they try 100 different breakdowns of BMI groupings until they found one that (barely) satisfied statistical significance?

    I remain skeptical as to the conclusions of this paper.

  28. Re:But what's your suggestion? by Fred_A · · Score: 4, Funny
    A suggestion I heard was ratio of fat weight over muscle weight. Don't know how to calculate that though.
    Easy, take a core sample and measure the various tissues.

    "now this may sting a little"
    --

    May contain traces of nut.
    Made from the freshest electrons.