Now it’s official. Starting next November, menus in many places where Americans eat — like chain restaurants and some movie theaters, convenience stores and amusement parks — will have to list calories.

Consumer health advocates were jubilant when the Food and Drug Administration announced the new policy on Tuesday. Many had fought for the rule for more than a decade, believing it would be a major weapon in the fight against obesity.

But will it?

The evidence on whether menu labeling works — either to move the national needle on obesity, or to reduce the number of calories an individual consumes after looking at a menu — is pretty skimpy, in part because the practice hasn’t been around that long.

In the few places where menu labeling exists, like New York and Philadelphia, most studies have observed a few thousand people over just a few weeks and months — too small a group and too short a time to detect the subtle changes that economists expect the policy will prompt.

Brian Elbel, associate professor of population health at New York University’s School of Medicine, has spent weeks outside fast food restaurants talking to customers and collecting their receipts.

The findings have been uninspiring so far. In a study he did in 2008 in New York City, only slightly more than half of consumers even saw the posted calories, and of those, a little over a quarter (around 15 percent of the total) said the information changed what they ordered. He conducted a larger study in 2010 in Philadelphia after that city started requiring chain restaurants to post calories, and the results were similar.

To read more, click here.

Jeffrey R. Ungvary President