I was wondering if I could still make the game around the theme presented when the jam starts, but with an artstyle related to fast food like pizza

The theme must be chosen from the list of themes released at the start of the jam.  If your game is pizza-themed it will be disqualified. 

(Eg. Just dont push it! Your game can have a pizza in it,  but it cant be 'about' pizza 👍)

thats sad