The week of Tyrofagos is between Shrove Sunday and Cheese Sunday is the week in which we eat fish, milk, eggs and cheese. This is called "white fasting"
The week that starts from the Monday after the Sunday of abstinence is called "Cheese Week" or otherwise known as "white week" because during this week Christians do not eat any meat in order to be ready for the great feast fasting of Lent.
This week Saint Theodore the Studite calls it "pronestimon" and the hymnography "prokatarsion", because it prepares us to pass through Lent.
So the Sunday immediately before the beginning of Great Lent is popularly known as Cheese Sunday or Cheese Sunday and it is a day with many folklore events in Greece.