When your holiday calendar is chockablock with family obligations, school recitals, secret missions to the mall, etc., something has to give. Enter “fast” food. But convenience doesn’t have to come in a takeout bag. One trick recommended by registered dietitian Keri Gans, author of The Small Change Diet ($15, amazon.com), is to keep a rotisserie chicken on hand. Then “bake a potato in the microwave, steam fresh or frozen vegetables, and you have a meal,” she says. If you must—and undoubtedly the time will come when you will need to—cruise through a drive-through or do takeout, know which are the smartest choices: the grilled-chicken sandwich instead of the burger, soft tortillas instead of crispy tacos. See a full rundown of healthy fast-food choices.