Check out reviews of other people to find out where the closest cafeteria or a diner is that is visited by the employees. This is where you can find a meal that costs the same as a coffee in the Duty-Free zone. It’s much easier to handle jet-lag when you are not hungry.

Some kinds of food can be taken on board; for example, a high-calorie bar, chocolate, or nuts. Carry an empty plastic bottle with you, and after you go through customs check, pour some water in it from a public fountain.