Have a banana before bed, says Saundra Dalton-Smith, MD, an internist and the author of Set Free to Live Free: Breaking Through the 7 Lies Women Tell Themselves. "Bananas are an excellent source of magnesium and potassium, which help to relax overstressed muscles. They also contain tryptophan, which convert to serotonin and melatonin, the brain's key calming hormones." Try this tasty and incredibly simple bedtime smoothie: Blend one banana with one cup of milk or soy milk (and ice, if desired). Pour and enjoy!