No, they wouldn't, they would eat lunch in the middle of their day, which would be centered around the times the sun rises and sets. Just like how days work eve

No, they wouldn't, they would eat lunch in the middle of their day, which would be centered around the times the sun rises and sets. Just like how days work everywhere pretty much. They just would know what those times are where they live naturally, and know that they can schedule a conference call with someone in London without getting the time off by +/-2 hours depending on if they do the time zone changes properly, know the time zone the other person will be in at the time, know if they are in or out of DST at the same time, etc.