''Eating is The Joy of Sex transformed into The Joy of Cooking,'' says Bunny Crumpacker in The Sex Life of Food, a sweeping look at how food, sex, and desire are intertwined. She examines the history of wedding cakes, the menu of the seduction dinner through history, and the aphrodisiac power of chocolate. In appraising comfort food, for example, she reports that during a phone-outage crisis at the Waldorf-Astoria, the Manhattan hotel ran out of its famed chocolate mousse. Stress, it seems, makes people want to eat something soft: ''Comfort in a spoon, and chocolate to boot.'' She surveys food eccentricities (some people have phobias of any nonwhite food) and notes that Lizzie Borden gave her parents the ax after being forced to eat mutton three times a day for a week. But back to sex: At the end of the book, Crumpacker includes recipes for famed aphrodisiacs like eau-de-vie and Russian cream.