Big Macs contain burger and lettuce. They have to be freshly made and handed to you or either, (a) The lettuce wilts of (b) the burger gets cold.

The quarted pounder with cheese is a better option at MickyD's but The whopper at burger king, with its fresh lettuce and tomato is better still. I like the whopper Jr. because a Whopper is too much food at a sitting for me in my middle age.