The legislation, introduced by Supervisors Rose Jacobs Gibson and Jerry Hill, would affect chain food-service establishments that have at least 15 outlets throughout the state.
"This is an opportunity for people to understand what they're eating, to make conscious and educated food choices in the future," Hill said.
The ordinance would affect approximately 30 restaurants and some grocery and convenience stores that sell food for consumption on-site, according to Jacobs Gibson and Hill. The establishments would be required to post nutritional information that includes total number of calories, and sodium and fat content of items on the menu.
The ordinance, which requires two readings to be adopted, will go before the full board again in September, according to Jacobs Gibson's office.
If approved, the ordinance would go into effect Jan. 1, 2009, Hill said.
The legislation was modeled on ordinances recently adopted in San Francisco and Santa Clara counties.