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.)

Comments

BMI is not accurate

[Harmonious Botch]

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.

Re:BMI is not accurate

[sumdumass]

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.

Re:BMI = Worthless

[Keebler71]

(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.

Re:Not hiring!

[NOLAChief]

Hooray gross generalizations. Have a counterexample: A few years ago my wife (who until that point had been a stick all her life) suddenly started gaining weight with no change in her reasonably healthy eating habits. She tried all the usual methods of losing weight (eat less, exercise, blah blah blah) but still kept gaining. Many people, including the majority of her doctors, had the same asshole attitude as yours and assumed it was her fault. The doctors finally figured out that her body had reacted to her asthma medication causing a form of Cushing's Syndrome. Her body stopped producing the hormone cortisol, which regulates weight. It was no self-discipline issue.

She remains a brilliant (slightly biased opinion, but not by much) chemist (pretty much disproving the original article), and now that the hormone is regulated, she has lost most of the weight she gained, though she remains scarred from the experience. And trust me, were she looking for a job from you, you bet your butt you would be sued under EEO and ADA laws. You can probably plan on that anyway. Hope you've got a good lawyer.

Re:Timothy has low IQ?

[killjoe]

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.

Re:BMI = Worthless

[tverbeek]

IQ tests are a reliable measure of one's ability to perform well on IQ tests. You may choose to call that "intelligence" and wrap it all up in a tidy tautology, but that doesn't really prove anything.

While debating the methodology of a study is valuable and worthwhile activity, it tends to get in the way of what generalizations can be drawn from the data. Since there is a strong positive correlation between BMI and actual obesity (even if that correlation is not 1.0 due to factors such as highly muscular individuals), and there is a strong positive correlation between IQ tests and actual intelligence (due to cultural and educational testing biases) this data identifies a negative correlation between obesity and intelligence. That's interesting and potentially useful. Now it's time for studies with more precise methodology.

There certainly is a definition of "intelligence"

[mbkennel]

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.

Re:IQ Tests

[Somnus]

The puzzle is that IQ shows both high heritability (by studies of separated twins) and bias towards industrialized nations (Flynn Effect).

The obvious theory is that both genetics and child care (nutrition, education) are vitally important.