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 soda…it’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….