Not a fan of most fast food.
When I want to eat high calorie foods I'll go with candy (sour worms, black licorice, etc). Or I will make some food at home... tacos with massive heaps of guacamole, fried rice and chicken wings, etc. I do like a good pizza, but not fast food pizza.
How often? Candy.... once a day lol. Tacos, wings, etc? Once every couple weeks.