The usually tolerant President Barack Obama has no patience for how some people choose to eat a hot dog.

“Is ketchup on a hot dog ever acceptable?” Bourdain asked.

“No,” the president responded. “I mean that ... It’s not acceptable past the age of 8.”

Them’s fightin’ words, Mr. President.

Low plastic stool, cheap but delicious noodles, cold Hanoi beer. pic.twitter.com/KgC3VIEPQr — Anthony Bourdain (@Bourdain) May 23, 2016

So where do Chicagoans’ disdain for ketchup on hot dogs come from? According to the Chicago Tribune, Vienna Beef executive Bob Schwartz may have the answer. The executive wrote a book about the city’s love affair with the street food and aptly titled it Never Put Ketchup On A Hot Dog.

“Schwartz theorized that Chicago’s aversion to ketchup dates back nearly a century, when the ‘dragged-through-the-garden’ style of hot dogs made additional condiments unnecessary,” Tribute writer Kevin Pang noted.

You do you, Chicago.