Previous Zane books have told us how to tone and build up our muscles to create the body beautiful. Here we're told how to fuel that body for daily workouts and supply its muscles with nutrients to keep them in optimum condition. For most exercise enthusiasts, the Zanes recommend a widely varied diet with a carbohydrate-protein ratio of two or three to one. Body builders, however, are advised to consume equal amounts of proteins and carbohydrates except when training for competition, when extra protein is desirable. They include eggs as well as red meats in their recommended diet because both are high in protein and the latter contains zinc, vitamin B-12, iron and trace minerals. Although eggs and red meat are usually damned by today's nutritionists for their high cholesterol content, the Zanes contend that food is far less important in cholesterol production than stress, overeating or underexercising. Their recommended high carbohydrate foods are in the nutrition mainstream: whole-grain cereals and bread, nuts, seeds, baked potatoes and raw or nearly raw vegetables. Like everyone else, they would have us eliminate sugars, syrups, salt, additives and highly processed foods. Even though alcohol is laden with calories, they don't ban it entirely (it relieves stress and contains high-density lipoprotein, which seems to help ward off heart attacks). The bulk of this work is devoted to a 21-day diet relatively low in calories, with a slightly more than two to one ratio of complex carbohydrates to protein. The recipes provide a wide variety of occasionally imaginative dishes. Their preparation, however, is much too time-consuming for most working people. Who, for instance, has time to whip up for breakfast a frittata of yellow squash, zuccini, onions, peas and eggs and make in advance for lunch a thermos full of pasta with tomato-mushroom sauce along with a tossed salad? A commendable effort on the whole, with little of the rah-rah cheerleading that makes so many of this genre distasteful.