The Health Blog has heard lots of anecdotal evidence about the effects of the kind of menu-labeling law that took effect in New York a few years back (and will go national under the health-care overhaul law). People tell us they never realized how many calories were in their daily Starbucks scone or Cosi sandwich until they saw the number posted in black and white.
But in practice, research hasn’t backed up the notion that putting calorie counts on menus actually produces big changes in people’s purchasing habits. A new study published in BMJ, looking specifically at lunchtime food purchases in NYC before and after the law took effect, doesn’t buck that trend.
Researchers involved with the study, which was funded by the City of New York and Robert Wood Johnson Foundation, surveyed 15,798 adult customers of various restaurant chains in 2007 and again in 2009. Researchers also looked at register receipts to verify purchases.
And they found no significant change in average calories customers purchased before and after the labeling law took effect: 828 calories before the law, 846 after.
The study did note that average calories per purchase fell at three chains — McDonald’s, Au Bon Pain and KFC. But those chains had also changed their menu offerings to include more low-calorie options.
“Those new products likely did more to influence average calories purchased than did the labeling, or at least [researchers] have no way to know if they did not,” Eric Finkelstein, an associate professor of health services at Duke-National University of Singapore Graduate Medical School, tells the Health Blog via email. (Finkelstein was the lead author of a study published in January that found a Seattle-area menu-labeling law had no effect on the calories people purchased.)
Lynn Silver, co-author of the BMJ paper and director of the Office of Science and Policy in the NYC Health Department’s Division of Health Promotion and Disease Prevention, tells the Health Blog the labeling laws themselves may prompt the addition of lower-calorie items. The thought is that no one wants a menu board full of high three-figure calorie counts.
But when restaurants decide to promote size and value rather than nutrition, the average calories per purchase can rise. That’s what happened after Subway introduced its $5 Footlong sandwiches, the study found.
Researchers also reported that 15% of the customers surveyed in 2009 said they used the calorie information when they made their decisions, and that they purchased 106 fewer calories than those who didn’t report using the information. Silver says that people who use the data “are successfully buying fewer calories.”
That may be true, but those health-conscious purchasers might be buying fewer calories than everyone else even without the calorie counts, says Finkelstein. Had the same people been surveyed before the law went into effect, they were probably the ones who’d report buying diet soda instead of regular, or a chicken sandwich instead of a quadruple cheeseburger. There’s no way to know whether the posted counts changed their behavior.
None of this is to say that the information isn’t worth having. Some people in the study did report using the calorie counts. Others may be using them in different ways — eating the same 800-calorie lunch, for example, but opting to cut back on dinner to compensate. Silver notes that a 2010 Quinnipiac University poll showed 84% of NYC voters found the information useful.
But it does show that if we decide that the calories consumed in restaurants play a significant role in obesity, simply posting the counts isn’t likely to be enough. People also have to make different choices.
Reported by Katherine Hobson