California on Tuesday became the first US state to force fast-food restaurant chains to post calorie information on menus and indoor menu boards, Governor Arnold Schwarzenegger's office said.
In the latest example of California officials seeking to encourage healthier eating habits, a bill signed by Schwarzenegger means restaurant chains with more than 20 locations must print nutritional information on their menus.
Although New York officials introduced a similar law in April, California is the first region to impose the calorie-count on a state-wide basis.
"This legislation will help Californians make more informed, healthier choices by making calorie information easily accessible at thousands of restaurants throughout our state," Schwarzenegger said in a statement.
Under the new law, restaurants affected must post calorie information on menus and indoor menu boards by January 1, 2011.
According to the California Department of Public Health, Californians have gained 360 million pounds over the last decade.
One in three children and one in four teens are overweight or at-risk, while obesity is listed as the second deadliest cause of preventable death among Californians after tobacco.
In July, California passed a law that would see artificial trans fats outlawed in restaurants across the state from 2010, before the ban is widened to all baked goods by 2011.
Separately, city councilors in Los Angeles approved a one-year moratorium preventing fast-food chains opening new branches in a poor neighborhood of the city plagued by obesity.