On long flights, I'm often given a very small bag of some kind of dried snack shortly (10-15 minutes) before a main meal is served - e.g. on a flight I was on yesterday, passengers were given a 10g bag of pretzels.
I'm wondering if this has some purpose beyond nutrition - e.g. to get people's digestion working and make the meal more comfortable / reduce competition for the facilities immediately after the meal?