Research on IQ and obesity is "problematic"

Noah Carl

Apr 16, 2021

We all know that IQ research is one of the most controversial areas of scientific inquiry. You have to be careful when talking about the genetics of IQ, and you have to be very careful when talking about group differences in IQ. However, one might have assumed that if you steered clear of genetics and group differences, you’d be unlikely to get into trouble. Not so, as a recent incident makes clear. (I should thank the Twitter user Whyvert for bringing it to my attention.)

Last October, Louis Jacob and colleagues published a paper titled ‘Association between intelligence quotient and obesity in England’ in the journal Lifestyle Medicine. Consistent with earlier studies, they observed a moderately strong negative association between IQ and obesity: just under 15% of those with an IQ of 120–129 were obese, compared to 21% of those with an IQ of 70–79. In other words: the brighter, the slimmer. The authors also found that the association remained statistically significant when adjusting for a range of other variables.

However, their findings were not warmly received in all quarters. On 26 February, the journal published a letter to the editor titled ‘Concerns regarding “Association between intelligence quotient and obesity in England” and unjustifiable harm to people in bigger bodies’. Despite comprising only a couple of thousand words, the letter has thirteen authors, which tells you something really needed saying.

After introducing themselves as “academics, health professionals, health psychologists and lay experts in weight stigma and discrimination, public health, patient advocacy and risk communication”, the critics assert that “the contents of this paper are likely to cause unjustifiable harm to people in bigger bodies”. I had assumed that ‘obese’ was the correct medical term, but that is evidently no longer the case. Perhaps if the original authors had referred to the “association between intelligence quotient and bigger bodiedness”, they could have forestalled some of the criticism.

Under Section 1 of their letter, ‘High risk of harm’, the critics write, “Publishing this study fuels negative stereotypes that people in bigger bodies lack intelligence—a dehumanizing stereotype that serves to deeply entrench discriminatory practices.” That escalated quickly. I would suggest the critics may have shot themselves in the foot here. Why should acknowledging a correlation between two traits be considered “dehumanizing”? Are they saying there is something wrong with having a low IQ? Half of humanity scores below average on IQ tests, so that would be quite an insulting thing to say.

The critics proceed to raise some very pedantic methodological points, which in no way undermine the basic correlation reported in the original study. For example, they claim: “the fact that the authors fail to highlight” the limitations of BMI as a measure of health is a “fundamental flaw in their study”. That may be a flaw, but it is hardly fundamental.

They also claim that “the research questions do not appear to have been generated with regard to PPI” (that is, Patient and Public Involvement). In their view, “the topic of this paper would not have been identified as a research priority by people in bigger bodies or members of the public more generally”. Personally, I am not convinced that giving members of the public (or the bigger-bodied community) a veto over research questions is the best approach to science.

Remarkably, the critics end by calling for the paper’s “retraction”, based on their “numerous, evidence‐based concerns”. However, they are willing to settle for “the publication of this letter alongside it to address the balance.” Well, they at least got their second wish: the original paper and the not-so-devastating critique can now be read side by side. I shall leave it to the reader to decide which represents the greater scholarly contribution.

Image: Charles Williams, A humorous comparison between the obese Daniel Lambert and Charles James Fox, 1806

Talk is cheap when it comes to “diversity”

I wrote a paper arguing that academics from overrepresented groups who are in favour of more “diversity” have an obligation to resign and give up their positions to members of underrepresented groups. It was published in Academic Questions. Here’s an excerpt:

In a paper dealing with the apparent inconsistency of professing egalitarian beliefs while enjoying a well-above average income, G. A. Cohen asked, “If you’re an egalitarian, how come you’re so rich?” This paper asks a similar question of academics who are members of overrepresented groups and purport to be in favor of more “diversity”; specifically, if you’re in favor of more “diversity,” how come you haven’t resigned?

Cancel culture does exist

I wrote a piece for UnHerd about cancel culture. It’s a response to a recent article by Tom Chivers, which claims the debate over cancel culture is futile because the people on each side are working with different definitions of that term. Here’s an excerpt from my piece:

I’m a fan of Chivers’ writing on science and culture, but in this case I have to respectfully disagree with him. He wants to take a middle path between — as he sees it — two equally zealous factions: those who claim cancel culture doesn’t exist, and those who argue it’s a very real problem. However, this isn’t a debate where the truth lies somewhere in the middle. Rather, those who deny that cancel culture exists are simply wrong.

Lockdown Sceptics

I’ve written five more short posts since last time. The first notes that the number of deaths registered in England and Wales is now 5% below the five-year average. The second reviews a study that found Dutch students “made little or no progress while learning from home”. The third argues that vaccine passports should not be required for outdoor sports events. The fourth argues that Boris Johnson is wrong to claim the lockdown has been “overwhelmingly important”. And the fifth argues that the case for lockdown collapsed when Sweden’s epidemic began to retreat.

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