JENNY CRAIG'S WHAT HAVE YOU GOT TO LOSE?

The proprietor of an international chain of weight-loss centers puts her program in print with this all-round advisory on taking and keeping it off. In context, it's nongimmicky, nontechnical in the extreme, moderate in demands, and sensible- -though that means that the message is also all-too familiar: Set goals that are reasonable and specific; don't diet without exercise; expect and learn from lapses; satisfy your taste with herbs and spices, not fat and sugar; be firm with saboteurs; and so on. In format, though, it is, if not gimmicky, at least busy. Chapters are ``modules''; food groups, following the American Diabetic Association model, are ``exchanges''; and the book is full of menu charts, assignments, self-analysis checklists, quizzes, lists, boxes, and ``Thank you, Jenny Craig'' letters from happy losers. Then there are recipes. None of this can substitute for group pressure or the commitment that comes from paying a boodle and signing up for scheduled sessions—but that could be said of any diet book. This one surely rates a hearing. (Line drawings throughout.)