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The influence of calorie labeling on food orders and consumption: A review of the literature1
Abstract
Obesity is a challenging public health problem that affects millions of Americans. Increasingly policy makers are seeking environmental and policy-based solutions to combat and prevent its serious health effects. Calorie labeling mandates, including the provision in the 2010 Patient Protection and Affordable Care Act that is set to begin in 2014, have been one of the most popular and most studied approaches. This review examines 31 studies published from January 1, 2007 through July 19, 2013. It builds on Harnack and French's 2008 review and assesses the evidence on the effectiveness of calorie labeling at the point of purchase. We find that, while there are some positive results reported from studies examining the effects of calorie labeling, overall the best designed studies (real world studies, with a comparison group) show that calorie labels do not have the desired effect in reducing total calories ordered at the population level. Moving forward, researchers should consider novel, more effective ways of presenting nutrition information, while keeping a focus on particular subgroups that may be differentially affected by nutrition policies.
I. INTRODUCTION
Obesity is a challenging public health problem. Being obese increases the risk of many chronic conditions, including diabetes, hypertension, high cholesterol, stroke, heart disease, certain cancers, and arthritis [1]. Nearly 36% of all American adults and 17% of children are obese [2, 3], with minorities disproportionately suffering from the disease [2, 4]. In recent years, obesity has also become a severe burden for the U.S. health care system, with total obesity-related costs exceeding $215 billion annually [5].
Fast food consumption has been linked to higher caloric intake and greater risk for obesity [6–8]. As an increasing number of consumers are dining at fast food restaurants [9], policy makers are giving attention to environmental and policy approaches that influence consumer choice, including mandated calorie menu labels in fast food restaurants. The 2010 Patient Protection and Affordable Care Act included a provision requiring restaurants with more than 20 locations nationwide to post calorie information at the point of purchase [10]. The legislation followed the actions of dozens of cities, counties, and states that passed their own laws requiring the posting of nutritional information in chain restaurants [11].
Calorie labeling as an obesity prevention policy holds promise. In its absence, nutritional information is difficult to access and understand [12]. Many consumers are not aware that nutritional information is available on pamphlets in restaurants or on restaurants’ websites. Of those who are aware, a very small percentage actively seeks out this information [13]. Consumers often underestimate calories in their foods, especially calories in items purchased from fast food restaurants [14–18]. As the total number of calories in a meal increases, so too does the consumer's underestimation of the total calories in the meal [14]. Furthermore, consumers want access to nutrition information [19–21], and report that they would to use it to inform healthier food choices [19, 22]. Therefore, calorie labels at the point of purchase could be an important and necessary source of information for consumers.
In 2008, Harnack and French published the first comprehensive review of the impact of calorie labels on food choice and concluded that calorie labeling had potential to affect food choices. However, the available evidence supported only “weak” or “inconsistent” effects. [23]. Although all but one study they reviewed demonstrated that calorie information may have a positive influence, the effects tended to be marginal and inconsistent across different categories of foods. At the time of their review, only six experimental, laboratory-based studies were available, as no jurisdictions had yet implemented calorie labeling. The studies reviewed included menu interventions at university and worksite cafeterias, as well as experiments where participants made hypothetical food choices. The authors concluded that the six articles reviewed contained “major methodological shortcomings,” and called for research conducted in natural settings.
In the years since that review, a number of localities implemented mandatory calorie labeling requirements for restaurants, and several studies examining the impact of the policies have been published. In 2011, Swartz and colleagues published an update to Harnack and French's 2008 review [24]. All of the studies in that review were required to have calorie labeling at the point of purchase or selection as a central component of the study; include original empirical evidence of the impact of calorie labeling on food choice; and use a natural, quasi-experimental, or experimental design. Thus, studies conducted in laboratory settings, some of which relied on hypothetical food selections, were excluded. The review ultimately examined seven papers and concluded that calorie labeling was not an effective way to reduce calories purchased or consumed [24].
This review builds on Harnack and French's 2008 review and uses less restrictive inclusion criteria than Swartz et al. (2011) in order to assess the evidence on calorie labeling published since 2008. Thus, we include studies examining hypothetical food selections. Properly framed, the results from these provide insight into how calorie labeling at the point of purchase affects food choices and how this policy can be improved. We are also very clear about how to differentially view these studies as compared to other work. In advance of the national expansion of calorie labeling, this article summarizes the state of knowledge about the effectiveness of calorie labeling and offers suggestions for future research.
II. METHODS
Search Strategies
A literature search was conducted through two online search engines - PubMed and Google Scholar - for articles published from January 1, 2007 through July 19, 2013. The search term combinations used in Google Scholar were Menu nutrition labeling + choice or purchase or order and restaurant or “fast food” and in PubMed were Restaurant OR Chain* OR Fast Food OR Cafeteria AND Menu OR (“point of purchase” OR “Point-of-Selection” AND Label* OR Calorie* OR Information.”. The main outcome of interest is change in total calories ordered. We also paid attention to self-reported awareness and use of calorie labels.
Inclusion and Exclusion Criteria
All articles were published in or after 2007, the year that Harnack and French (2008) conducted the last comprehensive literature review. Studies were excluded if they did not examine calorie labeling at the point-of-purchase or point-of-selection, relied solely on self-reported use of calorie labels or only focused on participants’ attitudes toward calorie labeling. Review, editorial and commentary articles were excluded. Relevant information from all articles were entered into a Microsoft Excel spreadsheet to facilitate comparison.
The initial search produced a total of 503 titles, 103 from PubMed and 400 from Google Scholar. After an eligibility screening of titles and abstracts, 402 papers were removed for being irrelevant (i.e. studies unrelated to the influence of calorie labeling specifically, or those that did not focus on food choice). Following that process, an additional 27 duplicates were removed. A total of 74 studies remained for a full text screening. Forty-three studies were excluded for being off topic or not meeting the inclusion criteria. The remaining 31 studies are reviewed in this paper and organized hierarchically into categories based on setting and study design. See Figure 1 for a more detailed description of the search process.
We divided the studies into the following categories, from strongest to weakest study design: “real world” settings, which include fast food restaurants or cafeterias, and “laboratory settings”, which include other controlled settings where participants either ordered and consumed meals or simulated their food selections based upon imitation menus or scenarios. Research has shown that people make choices differently in contrived settings [25], which is why we differentiate between studies conducted in naturalistic versus controlled settings. We separated studies conducted in fast food restaurants versus those conducted in cafeterias because the population in each of these is less generalizable to the general population.
We gave the most weight to studies that include a comparison group, as the use of a comparison group helps determine if the observed effects were attributable to calorie labels as opposed to other factors. In this paper, we first discuss studies focusing on purchases made at fast food restaurants that include a comparison group, followed by those without a comparison group. We then turn to studies conducted in cafeterias, first highlighting those that include a comparison group, followed by those that do not. Finally, we examine all studies conducted in laboratory settings, dividing them into two categories: those that examine actual food orders and consumption, and those that look at simulated food selections. For further details, see Table 1.
III. RESULTS
Overview of Study Characteristics
Setting: Of the 31 studies reviewed, 18 were conducted in “real world” settings and focused on actual food purchases [16, 26–42]. Twelve of these are natural experiments, conducted in locations where calorie labeling in fast food chain restaurants has been implemented, either by legal mandate or voluntarily by restaurants [16, 26–34, 39, 40]. Six were conducted in university or worksite cafeterias [35–38, 41, 42]. We discuss these studies separately from those focusing on fast food restaurants, because each of these involved an intervention designed specifically for patrons of these dining halls. The remaining 13 studies were conducted in controlled laboratory settings and utilize experimental designs to measure the impact of calorie labels on food choices [13, 17, 22, 43–52]. Three analyzed the effect of calorie labels on total calories ordered and consumed during an organized study meal [13, 44, 45], and 10 examined the role of calorie information on menus in hypothetical food selections [17, 22, 43, 46–52].
Measures and Samples: Twenty-three studies in this review include a survey component to examine if and how fast food consumers use calorie labels when deciding what to order [13, 17, 22, 26–29, 31, 33, 37–48, 51, 52]. Eight studies quantify total calories purchased or ordered using transaction data obtained from restaurants and cafeterias [16, 32–38], seven examine receipts collected from customers as they exited restaurants [26–29, 31, 39, 40], and three prepare foods on-site [13, 44, 45]. Of the 31 studies reviewed here, all but four examine purchases made by and for adults [29, 30, 48, 49]; seven of these focus on college students [13, 17, 22, 35, 37, 42, 46]. Of the studies examining real food orders, most attempted contact with all consumers present at the study site during the study period, such as lunch and/or dinner time[26–29, 33, 38, 39], or other busy times for restaurants [27, 34, 40] or cafeterias [41].
Category 1: “Real World” Settings: Restaurants
Twelve studies focus on purchases made at restaurants [16, 26–34, 39, 40], ten at fast food chains [16, 26–29, 31–33, 39, 40], and two at small sit-down establishments [30, 34]. Seven of these studies also inform on customers’ self-reported awareness and/or use of calorie labels when ordering food [26, 28–31, 33, 40]. Self-reported awareness of calorie labels varies in each study, from only 28% of customers reporting seeing calorie labels post policy implementation [28], to 57% [29], and 68% [30] of respondents reporting noticing calorie labels on restaurant menus in cities where the policy was implemented.
The reported use of this information is low in each study. Of the 57% of youth who reported seeing calorie labels in NYC's fast food restaurants, only 9% used the information when deciding what to order [29]. In another study conducted in NYC, of the 28% of fast food patrons who saw calorie labels, 88% reported being influenced by the information [28]. Finally, of the 68% of customers dining at restaurants in Seattle, 45% said the calorie labels informed their meal choice, and only 13% reported the information had an impact on what they ordered for their child [30]. Residents of low-income neighborhoods have been found to be the least likely to report using calorie labels to make a lower calorie food choice [28, 29], while those living in more affluent communities are among those most likely to use this information [27]. Women, more so than men, report using calorie labels [27, 40], as do those between 18-24 years of age compared to other age groups [27].
For the purposes of reporting the main findings of the papers reviewed, we distinguish those studies that included a comparison group from those that did not.
With a comparison group
Six studies utilizing a comparison group examined the influence of calorie labels on calories ordered [16, 28–32]. Five found no significant effect of calorie labeling on purchases [16, 28–31]. The only study to find a positive change was conducted by Bollinger and colleagues (2010), who analyzed over 100 million transactions from Starbucks locations in New York City (as well as two control cities, Boston and Philadelphia), before and after New York City implemented its calorie labeling law. After the introduction of calorie labels, total calories per transaction decreased by 6% (decrease from 323 to 247 calories), with 74% of the reduction attributable to customers purchasing fewer food items. Calorie labels were associated with a 26% decrease in calories per transaction among consumers who made high calorie purchases (upwards of 250 calories) [32].
Without a comparison group
Six of the twelve natural experiments reviewed did not include a comparison group [26, 27, 33, 34, 39, 40]. All but one found no significant impact of calorie labeling on purchases [26, 27, 33, 34, 39]. The remaining study found a small but significant decrease in calories purchased across the entire sample from baseline to a second post-implementation data collection, with even fewer calories purchased by women and those who reported seeing the labels [40].
Two other notable studies in this category deserve mention. Researchers at the NYC Department of Health and Mental Hygiene found that, among a subgroup of customers of a well-known sandwich chain, just seeing calorie labels at point of selection was associated with a decrease of 52 total calories ordered. However, they were unable to establish that this relationship was causal. Among those who reported using the information there was an average observed difference of 99 calories ordered compare to those reporting not using calorie labels to guide their food choice [26], though again questions of causality remain. In another study conducted by researchers in Pierce County, WA, calorie labels were associated with a decrease of 15 calories per order, as well as a decrease in other key nutrients typically associated with negative health outcomes, specifically fat (decrease of 1.5 grams per order) and sodium (45 milligrams per order) [33]. However, in the aforementioned study the implementation and duration of the voluntary calorie labeling in the restaurants varied across sites and may have affected the results.
Across all these studies, there is a trend toward calorie labeling having no effect on calories purchased at fast food restaurants. In nine of 12 studies conducted in localities where calorie labeling was implemented, the policy did not lead to a significant decrease in total mean calories or unhealthy items purchased [16, 27–31, 33, 34, 39]. However, seven of these nine studies did report significant relationships between calorie labeling and calories purchased within specific sub-populations, such as those who reported noticing the nutritional information, women, or those who were overweight [27–31, 33, 40].
Category 1: “Real World” Settings: Cafeterias
Three studies conducted in university dining halls [35, 37, 42], and three within worksite cafeterias [36, 38, 41] examined the impact of calorie labels at point of selection on patrons’ orders. In five studies calorie counts of select food items were accompanied by additional information, such as values of additional key nutrients [35, 37, 41], colors highlighting low vs. high calorie meals [36, 42], or photos of portion sizes [37]. Additionally, one site added healthier food items to the existing cafeteria menu and offered a nutrition education program to participants [36].
With a comparison group
Two of the six studies used a comparison group. One, a study by Ellison and colleagues (2013), found that although calorie labeling did not significantly alter total calories ordered relative to the comparison group, the presence of calorie information led participants to order fewer entrée calories. However, this difference was not significant when considering calories ordered from drinks, sides, or appetizers added together [42]. The other, a study by Webb and colleagues (2011), concluded that there was a positive impact of calorie labeling after consumers at the intervention site ordered more lower calorie items than those at the comparison site [38].
Without a comparison group
In the five studies that did not utilize a comparison group, calorie labeling demonstrated a somewhat positive impact on food orders, resulting in a decrease in total calories [35, 36, 41], fat [36, 41], or serving size ordered [37]. Also of importance, the introduction of labeling did not lead to a loss of revenue in at least one dining hall that reported this outcome [35].
Category 2: Laboratory Settings: Food Orders and Consumption Behaviors
The three studies that examine food purchase and consumption behaviors in laboratory settings returned mixed results [13, 44, 45]. Researchers at Yale University found that providing calorie information on menus led to a decrease in total calories ordered and consumed, with the largest decrease observed when calorie labels were accompanied by a statement with recommended daily caloric intake. In addition, after combining calories consumed during and after the study period, it was discovered that those given the calorie plus statement menu ate significantly fewer calories overall than did participants in either of the other two experimental groups [45].
While the other two studies did not report overall differences in the nutritional content of items ordered and consumed, they did discover significant differences among specific populations [13, 44]. Calorie information was more influential among dieters than non-dieters, and especially among female dieters [13]. Similarly, for those who reported that nutrition was important to them when ordering food, average energy intake was the lowest when presented with both calorie and price information on the same menu. However, males in that same condition consumed significantly more than their control counterparts [44].
Category 2: Laboratory Settings: Simulated Food Selections
Ten studies focused on simulated food selections wherein participants were asked to indicate what they would order from mock menus but did not actually order or consume food [17, 22, 43, 46–52]. All but one reported some positive influence of calorie labeling [17, 22, 46–52], with up to 44% of participants choosing lower calorie meals when calorie information was provided [47]. Of the two studies that examined gender differences in the presence of calorie labeling, one found that women ordered 146 fewer calories [17], and the other that men's purchase intentions for unhealthy items decreased [46]. Another two tested the effect of calorie labeling on food selections related to children. When parents chose for children, those given calorie information ordered an average of 102 fewer calories [49]. However, when children ordered for themselves nutrition information only affected the choices of those from high SES backgrounds [48].
IV. DISCUSSION
This review identified 31 studies that look at the effect of calorie labels at the point of purchase on food selection and/or consumption, of which 12 are natural experiments. The results of these studies demonstrate existing concerns about the effectiveness of calorie labeling policy. Authors of all the reviewed papers call for further research in this area. Some even suggest additional strategies to improve the effectiveness of this policy [27, 31, 36], such as nutrition education campaigns (34) or adding more healthful options to existing menus [33].
It is promising that most fast food restaurant patrons are aware of calorie labels on menus, as demonstrated in eight of the studies reviewed here which measure this outcome [26, 28–31, 33, 38, 40]. However, providing this information at the point of purchase is not enough to influence purchasing behaviors of most fast food restaurant consumers. Some studies show that certain groups are more likely to use calorie information while making their meal selections—such as women [17, 27, 40, 42], residents of wealthier neighborhoods [27], consumers who made very high calorie purchases prior to the mandate [32], dieters [13], and those who reported being motivated by nutritional information when making food decisions [30, 31, 44, 46]. Yet, there is an abundance of evidence that suggests calorie labeling, as it is currently being implemented, has no impact on overall food purchases or consumption for the population as a whole.
Limitations and Strengths of the Evidence
The studies reviewed in this paper have several limitations. First, there are a wide variety of settings and only a limited number of studies within each setting. Three studies sampled at only one chain restaurant [16, 32, 39], two were conducted in full-service restaurants [33, 34], six took place in cafeterias [35–38, 41, 42], and three were done in laboratory settings with mock menus [13, 44, 45]. In addition, six of the twelve natural experiments sampled in either exclusively low-income neighborhoods [28, 29] or non-fast food settings [16, 32–34]. This diversity means the results are not generalizable to all food outlets or consumers that menu labeling policies might affect.
Second, methodologies are not consistent. The lack of a comparison group in ten of the eighteen real world studies [26, 27, 33–40] makes it difficult to determine whether any of the observed effects of the policy are attributable to menu labeling, or if other factors were responsible. This problem is compounded by the absence of subgroup analyses across the majority of the studies, be it due to a small sample size [28, 29] or no survey data collected [16, 32]. Thus, with only about one third of studies specifically examining subgroups [13, 17, 27, 30–32, 40, 42, 44, 46], there is little insight into whether specific groups of fast food consumers may have been affected by menu labels or how strong that effect might be. And, none of the controlled studies included in this review found any effect of any meaningful magnitude, even if not significant. Furthermore, ten studies relied on hypothetical food selections [17, 22, 43, 46–52], making it unclear whether the participants would have behaved similarly had they been ordering real food.
The timing of data collection in the reviewed studies is another limitation. Most of the studies examining purchases at fast food restaurants were conducted over a short period of time and did not capture any potential long-term impacts of menu labeling [26–30, 33, 39]. Only one study continued to collect data for up to 11 months post calorie labeling implementation [32]; two studies include an additional wave of data collection to the one closely following the mandate [16, 40]. The results from this study are encouraging, as they seem to suggest that calorie labels may have longer term impacts on consumer behavior. However, because the study conducted by Krieger and colleagues (2013) did not use a comparison group the results should still be interpreted with caution [40].
Lastly, all studies conducted in a real world setting were only able to analyze the number of calories purchased—as reflected by receipt and sales data—and not what was actually consumed. Only the laboratory studies were able to look at this phenomenon, and the evidence from the majority of these studies suggests that the presence of menu labels does influence consumers to order and consume fewer calories in these laboratory settings [44, 45]. Further, because these studies focus on receipt and survey data collected on specific days, they do not report data on the frequency of restaurant visits and potential changes in restaurant attendance as a result of menu labeling policies. Thus far evidence from Elbel and colleagues (2013) in Philadelphia, PA indicates that frequency of fast food visits has not changed in response to the introduction of calorie labeling [53]. However this, too, is an area that deserves attention in future research.
On the upside, this review exhibits several noteworthy strengths. Although the variety of settings affects the generalizability of results, each study nevertheless provides an important glimpse into the impact of calorie labels on food choice in their respective settings—from localities where calorie labeling policies were implemented or mandated [16, 26–34, 39, 40], to work or school cafeterias [35–38, 41, 42], even to controlled settings [13, 17, 22, 43–52]. Also, even though many studies did not find the desired results, positive impacts were observed among certain subgroups such as women [17, 27, 40, 42, 46], those who reported being motivated by nutrition information [30, 31, 44, 46], or those who were overweight [30, 36].
Another notable strength in some of the reviewed work is study design. The majority of studies selected for review were conducted in settings in which participants made real food selections. Eighteen of these studies were in real world settings – fast food restaurants or cafeterias/dining halls [16, 26–42], and three were in laboratory settings which required participants to order and consume their selected meals [13, 44, 45]. Among them were a number of notable characteristics: nine had large sample sizes [26, 27, 29, 32, 37, 39–41, 51]; seven included a comparison group [16, 28–32, 42]; 13 utilized multiple measures, most frequently receipt data and surveys [26–33, 36–40]; and seven utilized transaction data obtained from food venues [16, 32–35, 37, 38].
Implications for future research/policy
As a group, the studies reviewed in this paper have set important groundwork for future research in this area. First, it is apparent that some fast food patrons are still not noticing calorie labels, and the percentage of those who both notice and use these labels to make food choices is low. Two qualitative studies, one that recruited from low-income neighborhoods in New York City [54] and another that recruited from fast food patrons in Philadelphia [55], have explored this issue and identified a number of barriers to calorie label usage. Schindler and colleagues (2013) cited the desire for quick, high calorie meals in spite of their nutritional content, familiarity with the menus (hence not even consulting them while waiting to order food), intentions to burn off the consumed calories later via physical activity, and lack of nutritional knowledge as reasons why consumers do no not use calorie labels [54]. Auchincloss and colleagues (2013) further identified confusing menu display, low expectations of nutritional quality, and sales promotions as reasons for lack of label usage [55]. More research needs to be done on this subject.
Second, the effectiveness of the current presentation of calorie labels on menus has been questioned by others, specifically the confusing nature of calorie ranges listed for menu items, as well as the size and placement of calorie information. After visiting 70 restaurants in NYC and rating 200 food items in an effort to determine how well calorie labeling complies with regulations, Cohn and colleagues (2013) discovered that although most of the restaurants visited displayed calorie information, in most cases that information was not sufficient for the average consumer to effectively use it. Calorie counts were often given for entire meals rather than for individual servings or food items, and calorie ranges did not specify which menu items fell at the lower and upper bounds. Furthermore, calorie labels posted online often differed from what was posted on restaurant menus [56]. In order for consumers to effectively use calorie information on menus, it has to be consistent and accurate everywhere it is posted, and the accuracy of this information needs to be enforced.
Third, it may be the case that calorie labeling alone is not sufficient to modify consumer behavior in the desired direction. Other presentation formats—traffic lights, physical activity equivalents, healthy logos, color coding, and the like—show promise beyond calories and even beyond relaying nutrition information [41, 43, 51, 57–59]. Thus, a simplified and more direct way of highlighting healthy food options may be a better way to inform consumers.
Fourth, providing the daily calorie recommendation statement at the point of purchase, and openly informing customers that additional nutritional information is available to those who wish to see it as currently proposed in the guidelines for national menu labeling may improve the effectiveness of the policy. The daily calorie recommendation could be a particularly beneficial reminder to those with low nutritional knowledge and low understanding of the meaning of calories. However, it's important that the additional information is presented clearly. Most menu boards in restaurants are already criticized for being crowded and difficult to read. The format in which existing and additional information will be presented should be strongly considered.
In the months leading up to nationwide implementation of mandatory calorie labeling, it is important to evaluate and understand existing evidence concerning the policy. While there are some positive results reported from studies examining the effects of calorie labeling, overall these studies show that calorie labels do not have the desired effect in reducing total calories ordered or consumed at the population level. Moving forward researchers should consider novel ways of presenting nutrition information, while keeping a focus on particular subgroups that may be differentially affected by nutrition policies.
Footnotes
1Research Support and Acknowledgement: This project was supported by grant number R01HL095935 from the NIH/NHLBI. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Contributor Information
Kamila M. Kiszko, New York University School of Medicine, Department of Population Health, Senior Research Coordinator 550 First Avenue, VZ30 6th Floor, New York, NY 10016; gro.cmuyn@okzsiK.alimaK.
Olivia D. Martinez, New York University School of Medicine, Department of Population Health, Research Data Associate 550 First Avenue, VZ30 6th Floor, New York, NY 10016; gro.cmuyn@zenitraM.aivilO.
Courtney Abrams, New York University School of Medicine, Department of Population Health, Program Manager 550 First Avenue, VZ30 6th Floor, New York, NY 10016; gro.cmuyn@smarbA.yentruoC.
Brian Elbel, New York University School of Medicine, Department of Population Health and New York University Wagner School of Public Service, Assistant Professor 550 First Avenue, VZ30 6th floor, 626, New York, New York 10016 Phone: 212-263-4283 gro.cmuyn@leblE.nairB.
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