As well as the obvious trick of avoiding clear culprits that may be laden with sugar or excessively stimulating spices, you can use food intentionally to help you sleep or to easily drift off.
Tryptophan is a naturally occurring amino acid that produces serotonin, essential for good sleep. Turkey, oats, seeds, and eggs contain it and lettuce contains lactucarium which has sedative properties.
To get to sleep fast, try a whole-wheat, seeded bread turkey sandwich with a relaxing chamomile tea for a sleep-inducing supper.