Trivialized in movies, ignored in homes, glorified on the Internet, eating disorders often get the best treatment on the page. For proof -- and inspiration -- take Kuffel's ''Passing for Thin'' and Wilensky's ''The Weight of It.'' Kuffel's story of ''Losing Half My Weight and Finding My Self'' -- that's 188 pounds, for you number crunchers -- is intensely personal, sometimes uncomfortably so. Tales of furtive childhood binges, public humiliation (being too big for a roller coaster), and self-loathing don't go down too easily. Wilensky's account, which examines her sister's dramatic weight loss thanks to gastric bypass surgery, is less personal: ''Why was Alison so fat, and how did she get that way?'' is the question she asks. Alas, answers are in short supply in both books. Fortunately, empathy, candor, and courage are abundant.