NYTimes run an article last year on "ego depletion", focusing on "decision making fatigue". Turns out sugar (M&Ms!) does play an important role in restoring the willpower and ability to make decisions.
1up for Witkacy! The Polish artist created a portrait firm in 1925 with a motto Motto: "The customer must be satisfied. Misunderstandings are ruled out". It operated according to a set of strict rules: "On arrival at the S.I. Witkiewicz Portrait Painting Firm, their portrait will be drawn according to the strict rules of the firm which they will read in advance". One of the offerings was drawing under influence, the influence (from coffee to peyote) dutifully noted on the portrait in chemical symbols.
http://www.nytimes.com/2011/08/21/magazine/do-you-suffer-fro...