Donald Trump’s bizarre views on health and physical fitness are, by this point, fairly well-documented. He told Dr. Oz he feels “the same age” as Tom Brady. He enjoys eating fast food because of its “cleanliness.” His doctor once even penned a note, in suspiciously Trumpian language, claiming that the real estate mogul would be “the healthiest individual ever elected to the presidency.”

Yes, this guy. Healthier than this guy. And this guy. Likely story.

And this week, reports resurfaced about how, in their book Trump Revealed, authors Mike Kranisch and Marc Fisher wrote on Trump’s unique theory of energy:

“After college, after Trump mostly gave up his personal athletic interests, he came to view time spent playing sports as time wasted. Trump believed the human body was like a battery, with a finite amount of energy, which exercise only depleted. So he didn’t work out. When he learned that John O’Donnell, one of his top casino executives, was training for an Ironman triathlon, he admonished him, ‘You are going to die young because of this.’”

Enter Stephen Colbert. “At the age of 70, Trump doesn’t have the energy of a child—in part ’cause he doesn’t believe in exercise. According to The Washington Post, Donald Trump believes the human body is ‘like a battery, with a finite amount of energy, which exercise only depleted,’” said the funnyman during his Wednesday night Late Show monologue. He added, “OK, good news, kids, there’s going to be a new presidential physical fitness test. See that rope? Don’t touch it. There, you passed.”

Of course, the human body actually becomes stronger with exercise. But not according to the president of the United States.   

“That, of course, is not how Donald Trump sees it. Apparently, Trump thinks a person is born with a finite amount of energy, which, may I point out, by that logic would mean the strongest people in the world are biggies,” joked Colbert.

“Though I suppose we should have seen his anti-exercise thing coming,” he continued. “After all, one of the first things Trump did was replace Michelle Obama’s ‘Let’s Move’ campaign with his own: ‘Let’s Not.’”

The Late Show host has, as you probably know, been locked in a war of words with the president ever since Colbert cracked on his late-night program: “In fact, the only thing your mouth is good for is being Vladimir Putin’s cock holster.” Trump’s online troll army then got the hashtag #FireColbert to trend on Twitter; Colbert refused to apologize; Trump called him “filthy” and a “no-talent guy” in an interview with Time; and then the comedian, as is his wont, took a victory lap.

The president’s response to this latest jab will, in all likelihood, involve the least amount of energy possible.