Does Posting a Calorie Count Change How People Eat?

Some time ago, we wondered if New York City’s new law requiring certain restaurants to post calorie counts might provide good material for academic researchers who care about obesity.

The answer: yes!

Brian Elbel, an assistant professor of medicine and health policy at the NYU School of Medicine and the NYU Wagner School of Public Service, was the lead researcher on a new study called “Calorie Labeling and Food Choices: A First Look at the Effects on Low-Income People in New York City” (abstract here; pdf here).

Elbel sent researchers into the field to measure the caloric habits of low-income people who eat at fast-food restaurants including McDonald’s and KFC. They gathered data before the calorie-posting law went into effect, in order to measure the change, and in addition to gathering data from New York fast-food restaurants, they also gathered data from equivalent restaurants in Newark, N.J., which doesn’t have a caloric-posting law, to serve as a control.

What did they learn?

“We found that 27.7 percent [of people] who saw calorie labeling in New York said the information influenced their choices.”

Great news, right? Um, no:

“However, we did not detect a change in calories purchased after the introduction of calorie labeling.”

Yikes. This is a great example of how well-intentioned incentives, even if they are successfully presented, fail to move the needle. There are obviously a million more questions to be asked in this realm. For instance:

  • As nudges go, is this one simply too subtle? How might a calorie nudge compare to a price nudge (some kind of a fat tax — on fatty foods, that is, not people)?
  • How might the response to caloric postings affect the choices of middle- and upper-income people?
  • If you want to curb obesity, especially among lower-income people, what do you do if it turns out that lower-income people are less responsive to the calorie nudge than other people?
  • Since this particular study relied on the subjects’ participation — the researchers intercepted them, inspected their receipts, and talked to them about their buying choices — what should we think about how representative these participants are? We write a good bit in SuperFreakonomics about how participants in most experiments are a) not likely representative of the general population — i.e., they are more cooperative — and b) likely to be influenced by the observers’ scrutiny and approval.

Personally, I think the calorie-posting law isn’t a bad idea at all. But I suspect that the people who will be most responsive to it, especially in the long run, are those who are already the most vigilant about their health and well-being. Think of it this way: what if the safest drivers on the road were the only ones to wear seat belts?


The results were actually even worse than what you mention - people actually ate *more* calories after the calorie counts were posted:


Not really a big shocker here, since the whole point is that if people have the option and they have caloric information they will make the right choice. But if you don't have the money to make economic choices, then the caloric information is irrelevant.

Plus really, are people really that worried about calories when you roll in the Micky D's or KFC? What would be more interesting is go to a non-fast food restaurant like Chili's and Applebees and see how the selection of salads changed. Since in general people get salads to "be healthy" but if you don't know the calories it is hard to gauge how you are doing in this, and here is where I would expect there to be a real impact. Also the add ons purchases at Starbucks, I would expect an impact as well.

Steve Kalman

Your subhead asks if the new law would provide good material for researchers. The answer to that was YES with a 100% certainty factor. No matter what behavioral changes, if any, occur, the before and after observations are grist for many academic papers.

For one anecdotal bit of evidence, I saw the calories in the optional flavorings Starbucks and similar coffee bars put into a medium latte. It made me switch to cappuccino. (I had guessed it would be high, but not THAT high.)


I suspect that those calorie counts will make the healthy healthier and, at best, not impact the unhealthy.

I was in NYC for several weeks this summer and that calorie information really did help me walk away from many unnecessary treats (who knew, really, really, knew, that a carrot muffin at Starbucks is over 300 calories?! I suspected it, but didn't really know till I saw it up there...urk). Can you guess whether I consider myself a healthy person? :-))

science minded person

I have been counting calories for more than 30 years. For me, it works. When I started, I figured that I could eat anything I wanted up to 1700 calories. For my height, Fifteen hundred or less, I was losing wait. 6 Entemens doughnuts later, I knew that if I ate more than salad, I would gain wait and I started to dislike eating sweets too much. Just enough to keep me satisfied at times. Now, I try to eat healthwise most of the time--except those good times and difficult times when chocolate or chocolate cake or hazelnut icecream and lemon sorbet just feels good.

What helped me is knowing the limits of what I can and cannot eat to maintain my weight. And now, I'm focused upon limits (diet and exercise wise) as far as maintaining my health.

But my guess is, every individual movesmore or less to the tune of their own drum. IF it works for you, that's what counts.


When I was in college, I'd always go and read the calorie information carefully on the muffins/snacks/drinks in the on-campus convenience store so I could optimize my per-dollar calorie count and get a meal (or a meal and a half!) for less than two bucks (milk and a muffin, usually...about 750 calories! 4 g protein)


My guess is that people have a general estimate in their head of which items on a menu are the worst, even if they don't have exact calorie counts, and to some extent that knowledge already guides their decision.

So when they say that the calorie count influenced their choice, they're really just replacing their estimate of an item's fat factor, which was already guiding their decision, with the exact calorie figure.

Over a large sample size, some estimates will be high, some will be low, and overall they will even out to result in the same purchasing behaviors. What surprises me the most about the lack of change in calories purchased is that it doesn't reflect any optimism bias in people's estimates.


I agree with both salient points in the comments above.

I'd love to see this study done at a Starbuck's and a Friday's or Applebee's. People know what they are in for at a true fast food restaurant; the calorie counts are probably not unexpected. It's places outside of McDonald's and KFC that would be more interesting to study.

Also, I think it would be more interesting to study this across the income spectrum. Diets are so tied to income that isolating a certain population introduces a separate set of inputs.

Everyone I know has a story about how they skipped a muffin or switched away from frappuchinos or ordered better when they boss took them to Friday's. Anecdotally to me and the people I interact with, the calorie counts have made a difference.

But when I crave a Big Mac, I'm still going to get that Big Mac.


The study doesn't support the conclusion that the calorie disclosures don't change people's eating habits, because the researchers didn't analyze people's total daily calorie intake. They only looked at their orders at the fast-food restaurant. But people who continue to eat their favorite meal at a fast-food restaurant even after knowing the calories may still take those numbers into account, by eating less at other meals to compensate.


I think what's missing in all of this is the fact that most people have no idea how many calories they should be consuming on a daily basis. It's easy to tell people to "count calories," but if they don't know the amount they should be ingesting to either lose or maintain their weight, then this information does them no good to begin with!

We need to do a better job of educating consumers on what their individual caloric intake should be. The RDA suggests 2000 calories - which can be quite low for someone who is extremely active, or quite high for someone who doesn't exercise or move around much.

Food for thought!


I'm a big proponent of calorie information on menus. However, without the basic understanding of what calories really mean (in my case that 3500 excess calories = 1 lb of weight gained and I burn about 2300 calories per day), the calories listed on menus is useless.

I'd be curious to know how many people when surveyed know how many calories they generally burn in a day?

It's like putting up a price list for someone who has no idea what a dollar is worth AND who has no idea how much money they have or make, and then asking them why their purchasing decisions aren't changed by the pricing information.


Did this study include an assessment of whether people knew approximately how many calories they should eat to maintain or reduce their current weight? It seems like there is a lot of variation in how of a grasp people have on the calorie metric, and that probably correlates with how much interest they take in their health in general. I guess the recent fad for expressing calories as a % of a 2000 calorie daily diet might be relevant.

Jason Stokes

I was impressed to see calorie counts at Dunkin Donuts in JFK terminal 5 a few weeks ago. I considered purchasing one variety of donut, then saw that another variety, almost as appealing, had around 40% less calories. I went with the lesser caloried donut and was far happier with my choice in the presence of the additional information.

I'm an upper middle class guy.


I should add that to my original comment, that you need the following:

- Money to allow financial choice
- Nutritional information to make nutritional choices
- And knowledge about nutrition and money so actually make a choice with.

With out the last, as people have pointed out in the comments, the information and the money do not matter. It would have been interesting to ask each participant actual nutritional questions to test their "nutrition IQ" and see how this also correlates. In fact this likely should be done for any study that looks in the affect of having nutritional information. I look at all the time the nutritional information when available (usually online before I go to a restaurant) to help make choices... Actually this information now dictates where I go to eat as well...


Re: comment 1 from Matt

If you read the actual article (not the NYTimes coverage) available on Health Affairs, you'll note on Exhibit 1 that while the calories purchased were slightly more, the difference was statistically insignificant.


Interesting to consider that buying choices may skew toward "getting the most calories for your money" buying at the lower end of the income spectrum. That would actually be a rational decision if money is tight.


A note that might apply when considering choices made by those with lower incomes: I was at Yankee stadium earlier this year starved and a little short on funds (I know, I could have eaten for a week for the price of the ticket). Since I couldn't afford the ideal balanced/healthy meal, I tried to judge the serving size based on the calorie count figuring that my best option was to go with the highest calorie/dollar ratio I could find in the hope that it would fill me up. Isn't it possible that the same thing is happening here in some cases?


Though it seems like if we want to take nutritional knowledge out of the "requirements", the instead of reporting calories seems like we should be reporting weight gained which is just calories divided by 3500... Since everyone understands weight, perhaps people don't just understand what it takes to control/lose weight.

science minded person

ps. my daughter has learned about carbs, transfats....... and, most of the time, won't even touch fast food where she does not know the ingredients and where the fat content is prohibitive. My step son (Adam Fox) is a vegetarian, taking many many vitamins daily. He had a radio show not too long ago on such subjects. It was a great show, but at the wrong time slot. My point, some aspects of eating habits are acquired even if they do involve choice.


No more effective than the dire warnings on cigarette labels. Not surprising, really. You look at the calorie count for the sandwich, it says 350 calories and you cry, "Supersize me!", thinking you're actually doing something good for yourself. Kind of like "light" cigarettes.