Both the first and CW lounges offer better food than you would get in the airport. Although the first dining room is very quiet and has good service, the buffet offering in CW lounge has a bigger selection (good salads and hot and cold options). Mrs MD and I base ourselves in the first lounge where the wine is marginally better and then take the buffet in the CW lounge. In my experience, very few people eat on board, preferring to get as much sleep as possible on what can be a very short flight, especially if you get any of the very strong tail winds of recent months.