Do Mandatory Calorie Information Laws Help?

Maybe not. See Mandating Calorie Counts: Has Libertarian Paternalism Gone Too Far? by Steve Sexton of Freakonomics. Excerpt:

"Existing research suggests that the benefits of such a revenue-less tax are minimal. Stanford economists, for instance, show that New York’s law reduced calorie consumption per transaction at Starbucks by a mere 6% and didn’t change drink consumption at all. Tracking the purchases of anonymous Starbucks cardholders, they found no change in individuals’ common drink orders that could be attributed to the law. Mandatory calorie labeling in NYC, they estimate, reduces long-term body weight by less than 1%."

See Calorie Posting in Chain Restaurants by Bryan Bollinger, Phillip Leslie and Alan Sorensen of Stanford.