This study showed mixed findings. Although, a greater proportion of NYC adults ordered a caloric beverage and regular vs. low-fat salad dressing after calorie labeling compared to adults in Newark, NJ, calorie labeling may positively influence a subset of consumers and their food decisions. For example, adults who reported noticing and using calorie labels to inform their food choices consumed more salads and ate out at fast food restaurants less often than adults who did not notice the labels. Adults who noticed calorie labels but reported not using the information also ate at fast food restaurants less often and were less likely to order caloric beverages than adults who did not see the labels. This suggests that calorie labels may provide some benefit to all consumers who observe them, regardless of whether they report using them. Though these results are promising, it is not possible to definitively attribute these favorable differences to calorie labels, because adults who notice labels may differ from adults who do not notice labels. Adults who notice labels, for example, may have a stronger interest in health, which influences their food purchasing decisions.
The mixed findings of this analysis may be expected when evaluating a single public health intervention in the absence of other environmental changes. It is possible that the effects of calorie labeling have a larger influence on the overall population. For example, calorie labels may have encouraged some adults to stop frequenting fast food restaurants given the limited availability of healthful options. However, a study of Starbucks transactions in NYC, Boston, and Philadelphia found that, following implementation of calorie labels, the mean number of transactions at Starbucks increased but the mean revenue per transaction decreased somewhat, leading to an overall neutral effect of calorie labels on sales revenue .
In this study, a difference-in-difference analysis revealed some less favorable behavioral differences after calorie labeling in NYC, including a greater proportion of adults who ordered caloric beverages and regular salad dressing compared with adults in Newark, NJ. Given the limited availability of healthy alternatives in fast food restaurants, it is possible that some adults have reactionary responses to the labels and decide to make less healthy choices given the relatively small caloric benefit for making a more healthful decision - particularly if adults believe that the healthier options taste worse.
A recent study in Pierce County, Washington found that calorie labels voluntarily put on printed menus reporting the calorie, fat, sodium, and carbohydrate content of meals led to a significant reduction in the caloric and fat content of meals in approximately 20% of surveyed patrons . Although the restaurant patrons reduced the caloric content of their meals by approximately 75 calories and fat content by 1.5 grams, more than 40% said that they noticed the information but did not make substantial changes to their food choices . In another study, after calorie labeling, Starbucks patrons purchased 6% fewer calories on average (for a 12 calorie decrease), with most changes coming from lower calorie food items rather than beverages . More substantial calorie reductions were noted in an experimental study  that manipulated printed restaurant menus to include calorie labels with and without educational information about recommended daily caloric intake. Adults consumed nearly 250 fewer calories during dinner and after the meal if they had menus with calorie labels and information about the recommended daily calorie intake compared to adults who had menus with only calorie labels. However, in another experimental study, this information was present and no impact of labeling was seen .
The results of this study, in combination with the relatively modest findings of similar studies, suggest a need for environmental strategies and social marketing or educational campaigns to maximize the efficacy of calorie labeling legislation. Public health interventions targeting behavioral change may work synergistically with other environmental strategies with similar objectives; for example, calorie labeling in combination with an increased presence of healthful food offerings in low-income neighborhoods and educational campaigns about total daily calorie requirements may lead to substantive behavioral change.
Research examining the most effective method for disseminating calorie information is also needed. For some menu items (e.g., burritos), it is allowable to post calorie ranges; often these ranges can spread more than 500 calories, making them difficult to interpret. Nutrition labeling on food packages has existed for some time now, yet a recent Health Canada survey notes that consumers still cite confusion interpreting labels as a barrier to their usage . Further analysis may reveal that calorie labels must be both clear and specific to be maximally effective. Even labels that exclusively list calories are not necessarily very meaningful to consumers. Wisdom, Downs, and Lowenstein  presented consumers with a choice of multiple snacks and provided the calorie information in one of ten forms. In the numerical information conditions, consumers were presented with calorie information alone, calorie information with daily reference intakes, recommended calories for a snack (200), the percent daily snack calories, or the number of minutes on a treadmill it would require to burn the calories in the snack. Other consumers were presented with heuristic cues like a nutrition grading for each snack, a traffic light rating, or an expected body size for individuals who chose each snack. Overall, the heuristic cues, particularly the traffic light and expected body size conditions, were most effective though numerical information about calories did lead to some reductions in calorie intake. Treatment effects were stronger in overweight rather than normal weight consumers. Given recent evidence that most consumers are unaware of the number of daily calories needed to maintain their weight , it is more likely that calorie information will improve food choices when the information is easily translatable.
Beyond calorie labeling, it is important to consider the potential response of industry to this legislation. Calorie labels may encourage restaurants to formulate healthier tasty menu options to continue attracting a wide variety of consumers. Restaurants attempting to support consumer health may find that merely making it easier to choose more healthful items can increase the respective sales volume and revenue. A recent study suggests that changing defaults is more effective than pure informational approaches (i.e., listing more healthful versions of food items on menus requiring consumers to actively request a less healthful version of that option). This type of 'asymmetric paternalism' where consumers are encouraged to make healthful food choices while still having the autonomy to make less healthful food choices plays on known consumer biases seen in behavioral economics . For example, consumers hold present-biased preferences, which means that they overvalue immediate rewards and costs compared with the rewards and costs of a delayed outcome [26, 27]. Consequently, when healthier choices are easier to make, consumers exhibit a preference for the benefit of convenience. Moreover, when the healthy choice is the default option, consumers are more likely to make that choice even if a different, preferred option is available. This type of intervention has been useful with increasing retirement savings  and increasing organ donation rates . Taken together, this suggests that calorie labeling has the potential to dramatically improve consumer well-being if labels are easy to interpret and if healthy choices become the default option.
There are a few important limitations to consider in the present study. First, this study was cross-sectional in design, and did not follow the same group of consumers over time. It is possible that the 4-week time period after legislation was enacted was insufficient to observe substantial behavioral change. However, the study of Starbucks transactions found that the small impact of calorie labeling in NYC was present immediately after labeling began . Also, this study had low power due to a small sample size of adults in NYC after calorie labeling legislation. It is possible that greater behavioral differences would have been observed with three larger groups of adults who did or did not see or use the labels. Although the NYC calorie labeling legislation requires that calorie information be printed in the same size font as the price, it is unclear whether all restaurants in this analysis were compliant with this requirement.
Importantly, this study surveyed "real world" consumers rather than utilizing a laboratory setting, which may be more representative of normal life circumstance. This study was designed to gather data from low-income and minority populations in order to examine whether groups disproportionately affected by obesity and related health conditions are positively affected by calorie labels. Receipt data were collected by research assistants; the study did not use retrospective self-reports which are prone to greater error. To reduce variability by restaurant type, the same restaurants were surveyed before and after labeling. Because data were collected both before and after labeling in NYC and in a comparison city (Newark, NJ), all differences observed between pre- and post- labeling in NYC are more likely related to the passage of calorie labeling legislation rather than to other larger population trends.