Stephen Colbert noticed a strange moment during Donald Trump’s weekend interview with reporter Sharyl Attkisson

“Attkisson asked Trump how he stays healthy,” Colbert said. “And he was weird.”

Colbert rolled the clip of Trump declaring one of the keys to his health is his diet.

“I try and eat properly,” the former president said told Attkisson, who quickly pointed out how much the former president likes hamburgers.

“I do,” Trump admitted. “But proper hamburgers.”

Colbert broke out his Trump impression.

“Proper hamburgers, not renegade hamburgers, not outlaw hamburgers,” Colbert said. “I only eat the most proper hamburgers. These are hamburgers wearing a necktie, a little top hat, and a sash that says ‘Mayor McCheese.’ How he screams when I bite him.”

See more in the Monday night “Late Show” monologue: