Republican congressman Aaron Schock of Illinoi' />

He's the youngest Representative in the United States House of Congress and probably the fittest.

Republican congressman Aaron Schock of Illinois has appeared on the cover of magazine Men's Health, exposing ripped abs more associated with movie star pin-ups than politicians.

The 29-year-old says he didn't always have such a physique - he was scrawny at school and didn't get into sport until college.

He said in the magazine: "In college I could feel my body changing, and I knew that if I didn't make some changes, I was going to go in the wrong direction.

"A lot of people don't think they have the time or the knowledge [to become physically fit], or they feel embarrassed to walk into a gym for the first time."

He also revealed in the magazine that such toned abs did not come without serious effort.

"It's got to happen early or it's not going to happen," he said.

Regular workouts were the only way to stay on top of the all-too-frequent Washington canape reception.

"You can pack a lot of calories on the end of a toothpick. You have a drink and a few hors d'oeuvres and you've just downed hundreds of calories.

"Exercise is more important than diet for me ... It keeps me in good physical shape and it relieves stress."

On the Today show, Schock was asked by host Matt Lauer if he was concerned about the photo from the cover coming up at the wrong time in his political career.

"There is some risk with it, but I think it's a risk worth taking," he said. "One of the biggest challenges our country faces is the rising healthcare crisis."

- Agencies