As we hit the road for the holidays, we're often faced with an unhealthy array of food choices at highway convenience stores. Marilyn Sparling, a registered dietitian at Duke University Medical Center, has tips for those holiday pit stops. The biggest problem, she says, is portion size. Big sizes mean more calories, fat, additives and sodium. Granola bars make good snacks, but check the nutrition facts. "Look at the label and don't get one of those high-powered, energy-type bars that carry lots of extra calories that most people just don't need." As for beverages, watch those big drinks. "They do have things like milk or chocolate milk, but they don't tend to carry the low-fat varieties. You can get 100 percent fruit juice and also juice drinks which don't have as much nutritional value, because they have so much extra added sugar. Of course, you can always get water. I think everyone should travel with a bottle of water in the car." Sparling says you'll eat better and save money if you bring along your own snacks. Dried fruit, grapes and carrot sticks are healthy choices and don't make a mess. I'm Cabell Smith for MedMinute.