"Orthorexia" ("correct eating") is a new coinage that describes an unhealthy obsession with sticking to your diet.
Bratman quickly forged his own dietary regime, eating only vegetables just plucked from the ground and chewing each mouthful 50 times.
"After a year or so of this self-imposed regime, I felt light, clear headed, energetic, strong and self-righteous," Bratman wrote in an account of his experience.
"I regarded the wretched, debauched souls around me downing their chocolate chip cookies and fries as mere animals reduced to satisfying gustatory lusts."