Thursday, November 08, 2012

Boosting Brainpower Without the Carbs

I'm a low-carb guy, thanks to my buddy Dave Asprey, who assures me of its benefits.  But one of the things that's worried me about the diet is the role of glucose in willpower.

Baumeister's work seemed to indicate that exercising executive function depletes levels of blood glucose--the famous example of Israeli parole boards comes to mind.  Simply drinking a sugary soda seemed to restore the executive function.

But for someone dedicated to the low-carb lifestyle, the thought of chugging a Sprite is anathema.  Even an orange juice seems like a remarkable indulgence.

Fortunately, it turns out that the brain is even stranger than we think.  It's not the sugar in the's the mere taste of sugar that restores our brainpower:
Crucially, half the participants completed the Stroop challenge while gargling sugary lemonade, the others while gargling lemonade sweetened artificially with Splenda. The participants who gargled, but did not swallow, the sugary (i.e. glucose-containing) lemonade performed much better on the Stroop task.

The participants in the glucose condition didn't consume the glucose and even if they had, there was no time for it to be metabolised. So this effect can't be about restoring low glucose levels. Rather, Sanders' team think glucose binds to receptors in the mouth, which has the effect of activating brain regions involved in reward and self-control - the anterior cingulate cortex and striatum.
 In other words, I can chug all the soda I want, as long as I spit it out.  Now if we could only do something about the cavities that would result....


Ryan Tanaka said...

Awesome, now my soda addiction is justified.

Along with the caffeine, it does give me a moment of clarity that I can't seem to get anywhere else (tea, coffee) so maybe that's what it was.

Andy said...

Why all the torture? Enjoy life. I'm 86 and never subscribed to all these diet tweaking behaviors. Remember, Atkins slipped and died. The lesson? Wear shoes that have above average traction and walk carefully.

Anonymous said...

Why are you low carb? If it's for staying lean, sorry!

Gary Taubes writes that tasting sugar, even thinking about the taste of sugar (do you feel the extra saliva enter your mouth to help breakdown anticipated food?) causes the body to release insulin to bring down the blood sugar levels that the body is expecting, which will cause any calories you do ingest to be stored as fat.

try again Harvard grad!

Andy said...

I think Anonymous is correct in his assessment that most folks from Harvard need to continually let people know they went there. I do know of one exception though; my cousin graduated from HBS in 2007 and has not yet felt the need to advertise it.