THE SKINNY ON KARL: All questions about how Karl Lagerfeld miraculously shed almost 90 pounds in 11 months will soon be answered. Lagerfeld and the doctor who supervised his complicated low-fat regime, Jean-Claude Houdret, are writing a book. To be titled “3D” — the D’s referring to a Designer, a Doctor and a Diet — it will be published by Steidl and released later this year or early in 2002.
Lagerfeld, who paraded the results of his efforts at the conclusion of the Chanel show Thursday, said discipline is the main ingredient behind his dramatic metamorphosis. But the book will contain recipes, photographs of the foods he ate, a question-and-answer section and an introduction by Lagerfeld. “It’s not an art book,” he said. “It’s a book for people who want to lose weight.” For Lagerfeld, the motivation for dieting was simple: the slim silhouette in men’s wear championed by such designers as Hedi Slimane of Dior Homme. “It’s all about clothes,” he said.

A SUZY Q: Will Suzy Menkes, fashion editor of the International Herald Tribune, attend the Louis Vuitton show scheduled for today? Banned from Givenchy on Wednesday by parent LVMH Moet Hennessy Louis Vuitton over the headline for her review of Christian Dior, the fashion editor did not attend the John Galliano show on Thursday night. Galliano’s house is majority-owned by the luxury giant. However, sources said that the LVMH ban has been lifted and her invitation to Vuitton stands. Menkes declined to comment on her intentions.