My experience for the best way to fall asleep is either dont eat anything a few hours before sleep (maybe except some fruit) after 7:30. Or to eat a very good meal and then fall into a very pleasant sleep (for example after one of the Shabb-t meals). Expecially with wine and meat (usually chicken) and all the other good food.
Also when my parents make this food called ploff, they put in it these black seeds (its called Zere in Bukharian), they also cause sleepiness and calmness.