The Los Angeles County Public Health Division has produced a “health impact assessment” of how nutrition information on menus might affect customers’ ordering practices. The authors say that if 10% of customers reduce their caloric intake from restaurant meals by 100 calories a day, they would avert nearly 40% of the weight gain expected among Los Angeles residents. This is all theoretical, of course, but the hypothesis is testable - and New York City is doing the experiment. The NYC calorie labeling project is very much in the works. The city is starting to issue citations to non-compliers, even though the whole thing is still in litigation.

Oops.  Note the comment from Christopher Jarosz, one of the authors of the study.  On this model, it’s 100 calories twice a week (sorry about that and thanks for sending).