Maintenance Meal Plans | 2. Food Group Serving Size Example. Breakfast. Grain 1 serving 1 cup ready-to-eat unsweetened cereal. Fruit 1 serving 1â. 2 cup cubed cantaloupe. Dairy 1 serving 1 cup skim or low-fat milk. Mid-Morning Fueling 1 Medifast Meal or 1 Healthy Fueling. Lunch. Vegetable 1 serving 1â.