John Schnatter, 47, hailed the nutritional value of his chain's pizzas during an interview with BBC Radio 4's "Today" program, saying: "Pizzas are healthy for you if you don't eat too much of it," The Daily Telegraph reported Friday.
However, he warned that the health benefits of pizza, which Papa John's does not sell by the slice, wane with higher quantities.
"You can't eat five or six slices," he said. "But if you eat one or two slices it's very nutritious. A slice or two is good for you."
The show's business presenter, Adam Shaw, joked that Schnatter's statement might upset shareholders.
"I'm not sure your investors would want to hear you tell people don't eat too much of our pizzas," he said.