Fast food restaurants in California will have to list calorie counts on each menu item under a new law signed by governor Arnold Schwarzenegger, his spokesman confirmed Wednesday.

The new law applies to restaurants with 20 or more locations in California, and encompasses more than 17,000 eateries. Beginning July 1, 2009, they will be required to provide brochures containing nutritional information including number of calories and grams of saturated fat. By January 2011, all menus and menu boards above front counters will have to include the number of calories for each item.

Schwarzenegger, a former world champion body builder, said the law would encourage people to make better nutritional choices and so fight obesity.

"This epidemic leads to major problems - diabetes, heart diseases, sleep disorders and depressions," said Schwarzenegger at a signing ceremony Tuesday. "It is no surprise that obesity is the number two killer in the United States right behind smoking."

California is the first US state to pass such a law, though the city of New York introduced a similar measure last July. California restaurant owners initially opposed the law, but came around after colleagues in New York reported that it had minimal impact on sales.

"You haven't seen numbers go southward - the business is still good," said Jot Condie of the California Restaurant Association. "Now it could be that someone exchanged French fries for something else - but if they exchanged it for something else, the bottom line is the restaurants haven't seen a financial impact."