Trouble sleeping? You’re not alone. More than 50 million Americans have trouble sleeping. Tossing and turning is frustrating, and the lack of shut-eye can lead to such health problems as an expanding waistline, high blood pressure and an altered mood. “Lack of sleep is a unique stress that induces a chronic stress response in the body,” says Shawn Talbott, nutritional biochemist, exercise physiologist and author of “The Secret of Vigor: How to Overcome Burnout, Restore Metabolic Balance and Reclaim Your Natural Energy.” Typically overlooked, one way to improve sleep is through diet: Just choose foods that can help you get more rest. Here are 12 foods that will help you fall (and stay) asleep.