THE F-PLAN DIET

F is for fiber--and this is an OK, if dull, not-too-low-calorie diet (1000-1500 calories a day). It differs from other fiber diets in one vital respect: Eyton is talking about dietary fiber (used by the body as fiber), not crude (visible) fiber; so the list of high-fiber foods includes potatoes and chickpeas, not just celery and bran. Dieters, she argues, will adhere to this low-cal regimen because: fiber slows down eating time (you have to chew more); you generally get more volume for fewer calories (fiber foods are bulky); fiber-rich foods have more taste (""the taste-evoking substances appear to remain intact within the cell walls, which have not been stripped away by refining processes""); and all that chewing also gives psychological satisfaction. Fiber and calorie charts are included, along with recipes; minute steak with parsley potato and zucchini, frankfurter and baked squash dinner, and artichoke pizza are typical fare. Since most recent, reputable low-calorie diets tend to be high-fiber anyway, and to contain ingredients of better nutritional quality, nothing about this makes it a must.