"We don't understand the neurochemical process of death," he says. "There's clearly something really profound that's occurring neurochemically in those final moments, presumably for the people who aren't decapitated or something like that" Autophagy represents the catabolic side of metabolism and breaks down old proteins to build new ones. The book is 410 pages long; it's a textbook as well,. Get it. There's so much good so much incredible information in here.