In a large saucepan combine onion, carrots, garlic, and water. Bring to boiling, reduce heat. Cover and simmer about 10 minutes or till vegetables are tender, stirring occasionally. Do not drain.
Stir in milk, oat bran, parsley, salt, nutmeg, and pepper. Bring to boiling over medium-hi heat, stirring constantly. Cook and stir for 2 minutes. Remove from heat. Stir in cheese till melted. Cool slightly. In a large mixer bowl beat egg whites till stiff peaks form (tips stand straight). Fold in vegetable mixture.
Pour into an ungreased 1 1/2 qt souffle dish. Bake in a 325 deg F oven about 50 minutes or till top is brown and a knife inserted near the center comes out clean. Serve immediately.
Per serving: 218 calories, 17 g protein, 19 g carbohydrates, 10 g fat, 31 mg cholesterol, 551 mg sodium, 460 mg potassium.