Naturally the King had to eat but not every meal was performed the same way. The Souper (supper) was at 10 at night but the King would also have another meal called the Diner (dinner). Often this meal took place in the King's own bedchamber and only men were allowed to be present. Only the King was allowed to sit during this ceremony which means that even those who had the right to sit otherwise was expected to stand. There was only one person whom this rule could be broken for: the King's brother who had the privilege of handing the King his napkin and would be invited to sit with the King once in a while (well, it is family is it not?).
Remember that when this meal was over the King had already gone through plenty of dishes before the Grand Couvert had even taken place!