Nutritional Analysis: One sandwich (prepared with fat-free mayonnaise, reduced-fat margarine and fat-free Swiss cheese; served on a hamburger bun) equals 239 calories, 6 g fat (0 saturated fat), 3 mg cholesterol, 846 mg sodium, 37 g carbohydrate, 3 g fiber, 11 g protein. Diabetic Exchanges: 2 starch, 1 lean meat, 1 vegetable.