Hip-hop star 50 Cent has sold millions of records serving kids from the hood to the 'burbs a steady diet of gangsta rap. Now, he's part of a new campaign to make his young fans healthier.

50 is a spokes-rapper and judge for a nationwide cooking competition aimed at preventing childhood obesity by improving high school students' eating habits. It is sponsored by Glaceau, the company partly owned by the rapper and that sells his grape-flavored Vitamin Water drink, Formula 50.

Student chefs in cities including New York, Los Angeles and Seattle will compete to create the most "nutrient-rich" cafeteria lunch recipe, Glaceau has announced. The winner will receive a $100,000 college scholarship.

Earlier this week, 50 said he thinks "it's a lot more difficult for kids" to stick to a healthy diet.

50, who has bared his washboard abs on album covers, said he wasn't always physically fit.

"I had all of the unhealthy habits," the rapper, 29, said. "Soda ... fast food, all those things."

Today, he exercises regularly and — thanks to a personal chef — eats nutritious meals.

"It's a better reflection of my lifestyle," he said. "I don't drink alcohol and I don't need an energy drink."