There is a slight variance depending on what class of service you fly, but in general you get a meal almost immediately after takeoff, usually within 30 mins of wheels up. And then the second meal usually occurs approximately 2-2.5 hours before landing. When I've had my kiddos on the redeyes, they usually have a snack or something before boarding and just skip the first meal service in favor of going straight to bed. However, with the longer flight times going west in the winter time, you do run the risk of them waking up hungry hours before breakfast. They do have snacks available in between, but nothing substantial unless you're in business class.