Wednesday 20 March 2019

An exhibition of motivated reasoning with Gary Taubes

If you've got a spare 2 hours and 37 minutes and are interested in the debate about carbs/obesity, yesterday's edition of the Joe Rogan Experience should be up your street. It features a showdown between journalist Gary Taubes and neuroscientist Stephan Guyenet.

These two have fallen out in the past over Taubes' belief that carbohydrates, rather than calories and inactivity, are the cause of the obesity 'epidemic'. Towards the end of the show, I was interested to hear that Guyenet started off as a fan of Taubes and his book Good Calories, Bad Calories, but that all changed when he looked at the empirical evidence.

I haven't read Guyenet's book, The Hungry Brain, but I follow him on Twitter where he posts some interesting evidence on nutrition. I haven't read Taubes' books either, but I've read about them and I've read some of his articles. I've also read The Big Fat Surprise which repeats his key claims about carbs and calories.

I was surprised by how little evidence Taubes brought to the table during the debate. While Guyenet was nerdishly citing numbered scientific studies, Taubes told stories and anecdotes. After all these years, his line is that he has a potentially important hypothesis and scientists should look into it. When told that scientists have looked into it at great length over a long period of time using every approach available to them, Taubes dismisses all their efforts as rubbish.

While accusing scientists of having a closed mind, Taubes more or less admits that the first thing he does when confronted with a study that goes against his theory is look for a flaw in the methodology (or question the impartiality of the scientist) so he can dismiss it. Since no study is perfect and no single study can answer every question, it is always possible to find room for improvement. In Taubes' mind, the slightest element of doubt is sufficient for evidence to be discarded in its entirety.

By contrast, he doesn't think his own hypothesis requires any evidence for it to be taken as seriously as the mainstream view. The failure of scientists to come up with studies that confirm it, even at his own institute, is just that - a failure of scientists. The video is worth watching as an exhibition of motivated reasoning and confirmation bias, if nothing else. 

Does Taubes have any doubts about his ideas, I wonder? Is there anything that could persuade him? I suspect that he has been writing about this for too long and has too much invested in it for him to ever admit that he got it wrong.

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