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.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....
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.