"We like all the sugary cereals. It's kind of funny; people give us a hard time for that. I'm 25. I'm still eating them, but he's 65 and he still loves them," said Jackson in a Web video.
"Honey Nut Chex, one of our favorites. Cocoa Puffs is one of the gov's favorites."
"We're peanut butter folks, if you can't tell already," Jackson added.
Jackson will be profiled on Thursday night's edition of "Rock Center," but NBC News posted a preview of the piece on its website.
In another Web video, Jackson is seen trailing alongside Romney as the GOP hopeful plays a prank on the press bus traveling with his campaign.
While the press corps is away, Romney posts a note on the inside of their bus that said, "You guys have it way too soft — nice ride. Mitt. P.S. Erased your hard drives."
The Romney campaign has been promoting the Republican contender's image as an endearing prankster in recent weeks.
"He does like pranks, although he doesn't like to get pranked," said Romney's son Josh on TBS's "Conan" Wednesday night, appearing along with his four other brothers. "We learned that the hard way."