Sippy-drink Theory of Willpower in Doubt

Willpower restoration by a real-sugar juice box (but not fake-sweetened version): also works if you don’t swallow (which doesn’t get much glucose to the brain, I guess - so it’s interesting that the real sugar gives the brain a reward signal that the no-cal fake sugar doesn’t, or: diet soda tastes worse).

via.

(see also my previous posts on willpower depletion)