Wednesday, August 1, 2012

Is Nutritional Science For Real? A Broad Experimental Design

Do nice abs speak louder than a nutritional science degree? Should they?

Interdisciplinary criticism poses a problem: tribal loyalties may unite insiders, but outsiders may geninely lack the theoretical knowledge to evaluate the claims of insiders.

I propose a general experimental design to test the expert claims of an entire field: in this case, nutrition science.

The nutritionists' case is timely, as the field has attempted to enforce its monopoly on anything resembling nutrition advice by, for instance, trying to shut down bloggers who discuss nutrition but aren't "certified." A legitimate question for the field of nutrition studies is this: is the special knowlege obtained by formal education in this field effective in solving the most important nutrition problems?

The most salient, widespread, and harmful nutrition problem in industrialized Western countries is obesity. My experimental design will test whether nutrition science, as a field, offers effective solutions to obesity.

In my view, a solution is "effective" if (a) when used, it reliably produces weight loss in obese people; and (b) it is "doable" - people are capable of putting the solution into practice. So even though a lettuce-and-fish-tea diet might be shown to produce weight loss in those who stick to it, it's not effective if most people can't stick to it. The human mind itself, including its limited willpower, is relevant to the solution.

Experimental Design

My experiment would test the claims of nutrition science as an entire field by measuring whether obese nutrition science students lose weight compared to matched controls enrolled in a program of comparable activity level.

An appropriate number of entering students in a nutrition science program (or more than one program) would be chosen as the experimental group. The control group would consist of a similar number of students enrolled in a similar education program in a subject unrelated to health or nutrition at the same institution(s), with similar demographics, overweight/obesity, and activity level.

Students in both groups would be weighed and have body fat percentages measured at the beginning of the experiment. Both groups would then have weight and body fat measured at the end of their programs, and perhaps five and ten years later.

The experiment is designed so that only the special knowledge varies between the experimental and the control group. (Suggestions welcome on how to better achieve this.)

If, at the end of five or ten years, the nutrition science students who were obese or overweight have lost weight (especially if they have become non-obese and non-overweight), and the healthy-weight students have not become obese, compared to the control group, that would be strong evidence that nutrition science provides effective solutions to obesity. Even if only 10% more obese nutrition science students than control students lost weight, that would be evidence that nutrition science has a true understanding of obesity that can be translated into real-life solutions.

However, if at the end of five or ten years, the nutrition science students have not lost more weight or remained healthier than control students, that would be some evidence that nutrition science, as a field, does not truly understand obesity in a way that can be translated into effective solutions, as define above.

This experimental design is not limited to nutrition science, of course. It could equally well apply to, for instance, therapeutic psychology; if psychology students become less depressed than control students, that's evidence of true understanding and effective methods; if psych students are not less depressed than control students at five or ten years, that would be some evidence that the special knowledge of psychology does not constitute a deep understanding of the problems it purports to address.

Thanks to @wonkinakilt on Twitter for suggestions!


  1. I smell a grant. Unfortunately, it's Ulysses and his wretched cigars.

    Thanks for coming.

    Seriously though, what most intrigues about this situation is not so much the wavering credibility of some nutritionists, but the wider social development, which dates back more than a century, of monopolized white collar professionalism in a post-guild, industrialized and urbanized America.

    Healthcare writ large is one looming example, with the AMA being the most obvious case of a modern professional organization locking down the practice of a trade and working hard to keep others out. The American Bar Association is another, and there are numerous other examples.

    Much of it was done during the Gilded Age and particularly the Progressive era, in the name of safety and science. And there is something to be said for it in terms of relegating snake oil salesmen and other charlatans to religion and get-rich-quick schemes, though one might argue its effectiveness is marginal; just look at chiropractice. But even to the extent it works, there are serious detriments as well, as you point out.

    Furthermore, the practice of licensing trades, including blue collar ones, has at times been used to discriminatory ends. For example, in the post-Civil War South, many highly skilled former slaves were effectively banned from practicing their trades because of discriminatory licensing laws that were passed specifically for that purpose.

    1. Absolutely the case - monopoly power. Licensing trades to exclude Jews is pretty much what happened all over Europe for hundreds of years - exactly because they are better at stuff in general, rather than to protect anybody from harm (as your ancestors were probably aware).

  2. Just because students are in a psychology program doesn't mean they are getting psychological treatment if the method is to be administered under specific conditions. In other words, perhaps it is not the knowledge of the science per se that is supposed to achieve certain results.
    I'd rather compare patients who are being treated by board certified psychologists to those being treated by pseudo professionals, such as career coaches and the like who use home made "recipes" to treat their clients.

    1. Indeed - same problems would apply testing medicine as a whole with my protocol.

    2. Nice point avrum, and I also like that Sister Y agreed with you. I am thoroughly enjoying this blog. If it were on video ie. a vlog, I would be wishing there was a written transcript to go with it. I heard sister Y on audio the other day nice to hear. Nothing to add, just cheering on both of you for the thinking.

  3. When I was on medical work experience somehow my friend and I managed to meet a nutritionist. We both tried to hide our sniggers at the absolutely useless job. Now I look back on the incident I wonder what emotion I should have felt for the job. Pity at how she probably felt inferior to the doctors around her who actually cure people? Hatred at how she is offering false hope to certain patients? Sadness at how the government is wasting even MORE money?

    One problem with your experiment though is that just because you CAN eat in a healthy manner doesn't mean you will do so. Though I suppose on the whole it'd probably work out anyway, just the correlation wouldn't be as good as you'd expect.


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