Don’t ask why I was reading the Journal of Personality and Social Psychology, but I thought this paragraph was funny.
Moreover, despite our manipulations, we do not intend to advocate consuming large quantities of sugar as an ideal strategy for improving self-control. Eating several candy bars, for instance, may give one a boost of energy and better self-control, but these benefits are likely to disappear when glucose levels eventually drop. Protein or complex carbohydrates may be more effective for sustained self-control. We used sugar in our studies because it is fast-acting and convenient. 
: “Self-Control Relies on Glucose as a Limited Energy Source: Willpower Is More Than a Metaphor”. Gaillot et al. Journal of Personality and Social Psychology 2007, Vol. 92, No. 2, 325–336