Organizers have recruited more than 200 restaurants across Philadelphia for the U.S. city's Healthy Chinese Takeout Initiative, which aims to reduce the food's salt content by 10 percent to 15 percent.

It's the latest effort by a major U.S. city to help people eat better. Many have already banned , and some require restaurants to post .

Philadelphia has focused on because 37 percent of residents have . The number jumps to 47 percent for African-Americans, according to a 2012 survey by the Public Health Management Corp.

The initiative, which began about a year ago, focuses on small Chinese restaurants because they are "an enormous industry" in the city, serving about 3 million meals a year, said Health Commissioner Donald Schwarz.

The dishes are cheap and easily available, especially in low-income minority neighborhoods that often lack supermarkets and access to .

But many residents—and even restaurant owners—didn't realize how the meals affected their health, said Schwarz.

Dietary guidelines recommend that Americans consume less than 2,300 milligrams of salt per day—about a teaspoon. Yet an order of chicken lo mein from local takeouts averaged 3,200 milligrams, while shrimp with broccoli had 1,900 milligrams.

Organizers offered a series of low-sodium cooking classes last summer with the goal of changing the ingredients but not the taste. Nine months later, in those two dishes was down 20 percent in samples from 20 restaurants. Researchers plan to test the food again in a few months, and expand the program to other items.

Participants have made several changes, such as flavoring orders with or garlic instead of sodium; using less sauce; distributing soy sauce packets only on demand; and posting .

Steven Zhu, president of the Greater Philadelphia Chinese Restaurant Association, recruited participants by saying healthier food could attract more customers. Still, some owners declined because they worried about losing business.

"Change is always not an easy process, and there was some reluctance in the beginning when we started this project," said Grace Ma, director of Temple University's Center for Asian Health.

Xue Xiu Liu, owner of Choy Yung Inn, said through a translator that he got involved to improve customers' health. Business is about the same, Liu said.

The Food Trust, a Philadelphia-based organization that promotes healthy eating, praised the city for working with the restaurants instead of blaming them. They are community gathering points and not going away anytime soon, noted spokeswoman April White.

"Let's find ways to make everyone a part of the solution," White said.