Leafy green vegetables
Leafy green vegetables such as kale, spinach, turnip greens, and mustard greens are excellent sources of calcium. The presence of calcium helps your brain use tryptophan to produce the sleep-promoting hormone melatonin (Jung, 2014). Eating a salad with dark leafy green vegetables for dinner can help you get the sleep you need.
Pretzels or chips
Pretzels and chips have a high glycemic index, meaning that they cause blood sugar levels to spike. While this is typically avoided in people who are diabetic, it can be helpful to promote sleep. This is because the insulin boost that comes with high blood sugar in healthy individuals helps to shuttle more tryptophan into your brain (Jung, 2014).