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New York Magazine’s Fact-Restricted Calorie Article

Starvation is clearly not a good route to take, even for a good science journalist.

I’m usually a huge fan of Julian Dibbell’s science writing, but this piece in New York Magazine perhaps inadvertently illustrates that the starvation diet he road-tested may not be so good for the brain.

In a well-written, witty story on extreme caloric restriction as a way to extend lifespan (which has been demonstrated in animal models, but not so far in humans), Dibbell reports on his experience of eating (tiny portions!) with its proponents.

Unfortunately, he uncritically cites one supporter’s claim that a brain chemical – brain-derived neurotrophic factor or BDNF – “creates optimism.” He notes the “manic gleam” in the speaker’s eye as he talks about the substance.  Other proponents of caloric restriction claim that, presumably as a result of BDNF, the diet makes them “exhilarated” and “euphoric.”

But BDNF has been shown to decrease in manic states and is associated with numerous different brain functions; no data supports it as the mediator of optimism, although restoring brain levels of it in certain areas does appear to help depression .  High levels in other brain areas, however, are associated with the dysphoric sensation of drug craving in addicts. Variants of certain genes for BDNF are even linked with susceptibility to anorexia.

Coincidentally, I read the article just after getting off the phone with a leading BDNF researcher, who warned me that the widespread presence of the substance in the brain makes drawing conclusions about its activity extremely difficult.

And chronic stress – like that which can be caused by long periods of food deprivation –
ultimately lowers BDNF, according to the research. This easily-checked mischaracterization of the BDNF research does not bode well for support of the idea of caloric restriction for science journalists.  It does suggest that checking scientific claims on PubMed before repeating them is always a good idea, though.