Abstract from Eugenia Cheng’s paper, “On the perfect size for a pizza”:
We investigate the mathematical relationship between the size of a pizza and its ratio of topping to base in a median bite. We show that for a given recipe, it is not only the overall thickness of the pizza that is is affected by its size, but also this topping-to-base ratio.
In other words, the smaller the diameter of the pizza, the fewer toppings you get in a bite relative to the crust. Even if the toppings are squid-rings, corn, and nori with hot mayonnaise sauce, you’re getting fewer of those (gag-incuding) toppings on each slice and in each bite.
A “large” Japanese pizza ranges from 31–36 cm (12–14 inches), which is about an American medium on the low end, to what would be a normal large for a chain like Pizza Hut or Dominoes. This also lends support to those who say that New York style pizza is the only truly good pizza. NY style pies are 18 inches in diameter and have a very thin crust, so you get a much better topping-to-base ratio per slice.