NYC Labeling Law Study

Megan "Four Apples" McArdle comments on (and, helpfully, links to the full text of) a recent study examining the impact of the NYC restaurant labeling law on purchases made by predominantly low-income, low-education minority-race customers at 4 fast-food restaurant chains.

The highlighted results: From examining receipts, the mean calories purchased by customers did not differ before and after the labeling law was passed, nor did they differ from a control group in Newark, NJ, where there is no labeling law (all were around 820 - 850 calories for a lunch or dinner meal). Those who reported that the calorie information did make a difference to their order did not differ in calories purchased from those who said it didn't. Labeling did lead to a higher proportion of customers being aware of the calorie labels, but no noticeable difference on behavior.

I'd say this is not great news, but I still think the celebratory "see, this wonderful study proves my already firmly-held opinions and thus I am right and the busybody public health policy makers are moronz!" tone of the comment section is a bit ... um, inappropriate.

This is one study. In the behavioral sciences, one study is hardly sufficient evidence to make sweeping claims about the effects of anything. I agree, this is not the kind of result that policy makers (and I) would like to see, and yet, it's not very surprising that favorable results were not found among this population. It seems like they purposely chose a population that was less likely to be responsive to the calorie data - they are poor, uneducated, and eat fast food an average of 5 times per week. This is a tough crowd. I agree with the researchers that this is an important population to study, given that they are at high risk of obesity and related health problems, but they aren't the only population we care about. (This is not to fault the researchers but to point out another way that this study hardly settles the debate.)

I could also nitpick the study methodology - they based calorie counts on food ordered, not food eaten; some people who were eating at the restaurants before the labels may have stopped eating there once they knew how many calories were in the food but they could not be included in the study; they looked at fast food but not other restaurants in which the calorie content might be more surprisingly high and hence more likely to give the customer pause* - but I think (on the basis of a very quick read) that this is probably a reasonably good field study for looking at the particular population they are interested in.

* Recall previous posts that cite many studies finding that perceptions of calories become more divergent from actual content the larger the calorie content gets. Also, like some of MM's commenters, I too have sometimes been surprised by how relatively few calories are in some fast food items, like a quarter pound burger or a small french fries. I think there is definitely an effect of food categorization on perceived health value (e.g. hamburgers are "unhealthy" and salads are "healthy") that influences how we react to fast food calorie information.

I was very surprised that they did not report standard deviations to accompany the group means, which I think of as the default reporting style (and I believe is required for many journals); I'd be curious to see if there was a difference in the distribution of calories for the customers ordering from menus with calorie data compared to the other groups. The presentation of calorie data could have led one group of people to purchase even more calories (e.g. those interested in getting the most calorie bang for their buck) while another group purchased fewer calories, for example, without changing the overall mean for the sample. They did report means for various socio-demographically-defined groups, but I wouldn't expect attributes like race and under/over 35 years of age to capture this kind of thing very well.

I would also have liked to see the calorie numbers broken down by things like weight or weight status (i.e. normal, overweight, obese) or dieting / health consciousness status, but they did not collect that sort of data in this study.

But that's OK - I am confident that researchers in this area will be (are) working on and publishing additional articles looking at this issue from a lot of different angles.

Also, Tam might like (as I do) the fact that NYC has rolled out an educational campaign that says, in a less psychological-reactance-inducing way "Eat less." To wit: "2,000 calories a day is all that most adults should eat." I wish them luck.