Psychologist and professor Seth Roberts has spent years analyzing why most diets don't work. A maverick with a curious mind, and a yen for self-experimentation, he started by asking a simple question most experts haven't tackled: What makes us feel hungry in the first place?After scouring the scientific literature and tirelessly testing various theories and practices, Roberts hit upon a simple, effective strategy for controlling the body's internal "set point"—that is, the thermost...