In Paradise, there is a special door called ar-Rayyan (الريان). It is other than the eight big doors of Paradise. On the Day of Judgment this door will be opened, and those Muslims who used to fast a lot, not merely fast the obligatory fasting and some optional days, will be called to enter Paradise through that door. An example of those who fasted a lot is the great scholar al-Bayhaqiyy (994-1066 CE)--he used to fast the whole year other than the 5 days on which it is not valid to fast. Also those who fast every other day enter Paradise through that door. Then ar-Rayyan will be closed, and no others will enter through it.