Judging from the confusion here, one could argue that the "two-pizza team" definition is also vague and meaningless - at least to an international audience.

The two pizzas solution can be easily explained by delivering an American style pizza and seeing if the team can eat it.

I can eat a family sized Papa Murphy's pizza by myself in one sitting so I don't know how relevant a metric that is.

It's not how much pizza you can eat.

Think how many slice a person typically eats at a team lunch in a professional setting. It's usually a few slices. A large pizza has around 8 slices, so with two pizzas, that covers 6-10 people. And that's what the article says.

Keep in mind you’re on a team. As a good team player would you be satisfied with 2 slices even if you could eat 6?

To be fair, we shouldn't have assumed that imperial pizzas are the same size as metric ones.