Excess adiposity contributing to the “obesity epidemic” is a public health concern in the United States [1
]. In 2011–2012, more than two-thirds (approximately 68.5%) of adults were overweight or obese (defined as a body mass index ≥25) [5
], an approximate 12% increase since 1988–1994 [6
]. The financial burden associated with the U.S. overweight/obesity prevalence combined is estimated at approximately 5–10% of total healthcare costs annually [7
]. Obesity is also associated with an increased risk of morbidity for several health conditions, including hypertension [8
], type 2 diabetes [13
], and cardiovascular disease [17
] among U.S. adults. Many factors may contribute to the prevalence of overweight and obesity, including environment, genetics, and behavior choices, such as physical activity and diet including excess caloric intake [1
]. Food consumed away from home, including foods from table-service restaurants, cafeterias, taverns, and fast food [23
], may be one such contributing factor.
U.S. consumer spending on food away-from-home has increased since the mid-1990s and is expected to continue to increase by approximately 18% at full-service restaurants and 6% at fast-food restaurants between 2000 and 2020, indicating the importance of away-from-home foods to U.S. dietary intake [24
]. The availability of fruits and vegetables, whole grains, and low-fat milk in restaurants is limited according to an evaluation of the nutrition environment in the away-from-home setting [25
]. Foods purchased away from home tend to have high energy per nutrient density when compared with foods consumed at home. Main and side dishes at sit down and fast-food restaurant chains consistently contained high amounts of fat, saturated fat and sodium, and low amounts of fiber and fruits/vegetables [26
]. An evaluation of approximately 3500 meals at 34 of the top 50 U.S. restaurant chains showed that 91% of meals did not meet dietary standards created by the National Restaurant Association [27
]. Thus, although food prepared away from home accounts for a significant share of U.S. food consumption, it may exert a disproportionately larger influence on the intake of nutrients of public health concern compared with food prepared at home [28
Several studies have proposed that food prepared away from home may be a contributor to overweight and obesity in the U.S. [29
]. Consumers were poor estimators of the calories contained in restaurant food items [36
] and the consumption of food away from home was positively associated with caloric intake [31
]. The lack of nutrition information in restaurant establishments was given as a reason for consumer difficulty in making healthy choices, suggesting a need for menu labeling [31
]. A variety of factors may influence away-from-home food purchases, but it is plausible that this type of nutrition labeling on menus in restaurant establishments would be used by consumers when a third of the population use nutrition information on packaged foods [39
]. In response, the Obesity Working Group advised the Food and Drug Administration (FDA) to encourage restaurants to provide nutrition information to help consumers make healthy choices [40
] and following this, a population-based public health initiative targeting food prepared away from home was implemented to help ameliorate the rising rates of overweight and obesity. Section 4205 of the Patient Protection and Affordability Care Act passed in 2010 required that chain restaurants and similar retail food establishments with 20 or more sites post calorie information for menu items at the point-of-purchase [41
] to help consumers make healthy choices when eating food prepared away from home.
Such far-reaching policy has the potential to effect overall U.S. away-from-home dietary intake. Several previous systematic reviews and meta-analyses have been completed to evaluate the impact of menu labeling on calories chosen in an away-from-home setting [42
] but evaluation regarding nutrient intakes, specifically carbohydrates, total fat, saturated fat, and sodium, has not been included. Estimation of the purchase or intake of these nutrients in the overall U.S. dietary context of excessive calorie intake, not including other populations [43
], and the special designation of saturated fat and sodium intake as nutrients of concern, is critical to determine how menu labeling may be influencing not only the quantity of U.S. caloric energy but also indicators in order to begin to quantify the quality of energy from foods consumed away from home. Adults primarily make away-from-home purchasing decisions, thus the previous systematic reviews of Long et al. [42
], Swartz et al. [44
], and Sinclair et al. [43
] including non-adults, do not provide clear information on adult populations. Finally, evaluation of purchase intentions only [45
], may not reflect actual ordering/consumption behavior among U.S. adults. Therefore, the novel hypothesis of this study was that restaurant menu labeling would not affect caloric choice or intake but would alter carbohydrate, total fat, saturated fat, and sodium choice or intake compared with before menu labeling or compared with a control group, in an away-from-home setting in the U.S. adult population. The hypothesis is based on the previous literature showing null or minimal differences in calorie choice and attempts to fill the gap of knowledge indicating whether menu labeling may impact chosen or consumed nutrients. Secondly, the effect of menu labeling in a natural away-from-home setting or in a lab environment was hypothesized to make a difference in the efficacy of menu labeling as an intervention to alter caloric choice or intake among U.S. adults. Data were handled to prevent the interference of interventions other than quantitative nutritional labeling (education, taxation, etc.) and a special emphasis on high quality study designs was implemented in order to inform future implementation of this policy intended to support the prevention and reduction of obesity and other chronic diseases.
The results of this meta-analysis showed no effect of menu labeling on calories chosen, either ordered or consumed, among U.S. adults in natural settings, thus supporting the hypothesis and previous findings. A significant difference of −115.2 calories was found when meta-analysis was restricted to studies conducted in laboratory settings. This is a minimal calorie value in the context of a daily and usual dietary intake but demonstrates how the setting may influence efficacy of this intervention. Novel meta-analysis of carbohydrates, total fat, saturated fat, and sodium resulted in no significant effect of menu labeling on choosing or consuming these nutrients in food away from home among U.S. adults. Menu labeling was expected to result in alterations in choice or intake of these nutrients on the basis of efficacy to improve dietary choice or intake that had previously been undetected in meta-analyses results of null or minimal changes to caloric choice and intake. The lack of significant nutrient changes, however, are tempered with acknowledgement of the few studies included in those analysis.
A laboratory setting is not the setting that menu labeling is intended for as a real-life intervention. The controlled and manipulated laboratory setting may likely influence the behavior of participants [51
]. For example, hunger may be differentially related to eating behavior in laboratory and real-life settings and this could lead to differences in caloric ordering/consumption patterns. Three of the five lab-based studies in this meta-analysis [99
] quantified and controlled for hunger in the analysis, but none of the real-life setting studies measured this quality. Thus, knowledge of how this factor may have influenced results among the diverse settings is not known, and thus future research is needed. Other variables that may influence an individual’s choice in an external environment may be not easily translated into a laboratory setting. Along with the nature and extent to which one’s actions are scrutinized by others, the particular context and process by which a decision is embedded, and the self-selection of the individuals making the decisions, may be very different and influential in food and beverages ordered or consumed in real world vs. laboratory settings [109
Previous studies indicate that taste [110
], cost [110
], accessibility [111
], and convenience [111
] are factors of higher relevance to patrons than nutritional concerns [110
]. These variants may not be observed in laboratory experiments where food options are often limited, the food is offered for free, and the influence of accessibility and convenience cannot be evaluated. Mohr et al. [112
] also identified a relative indifference to health consequences of behavior as one of the predictors of more frequent consumption of fast foods [112
]. However, the sample of participants who agree to participate in laboratory setting studies may not represent a group with a similar attitude and set of beliefs regarding health in such a setting. Thus, factors not related to nutritional labeling alone are likely to be influencing the decision of food ordering/consumption in natural settings compared with laboratory settings, limiting the usefulness of laboratory controlled study findings to real-world applications. The challenge of evaluating the impact of nutrition labeling to food ordering/consumption in natural setting studies may be inherent to the limited ability of investigators to identify and quantify the variant and perhaps multiple factors that control a particular behavior.
Previous meta-analyses and systematic reviews showed similar results of little to no difference in calories purchased/consumed due to menu labeling. Long el al. [42
] found that labeling was associated with a –18.13 ordered kilocalorie reduction per meal, however, when only studies with control groups in restaurant settings were included, no significant association was found. Similarly, Swartz et al. [44
] and Sinclair at al. [43
] found no correlation between purchased/consumed calories and menu labeling. Notably, previous meta-analyses included studies with online ordering, non-restaurant/restaurant-like setting (i.e., coffee-shops) and hypothetical ordering [42
], diverse age groups [42
], and studies conducted in countries other than the U.S. [43
]. These kinds of studies were excluded in our meta-analysis. We also included only studies adherent to stringent criteria based on CC&CRG guidance and classified as “A” and “B” (Table 1
) that included quantitative calorie/nutrient labeling. Despite these restrictions, high heterogeneity was still present. The high heterogeneity may be due to the diversity of study designs (RCTs, quasi-RTCs, BA studies, ITS studies, and cross-sectional studies), varying dining settings (fast-food restaurants, laboratory settings, and full-service restaurants), and different outcome measures (calories ordered or consumed). This diversity highlights a need for more studies in real-world settings that use standardized, criteria-specified, and bound study designs and methodologies.
Despite the finding of no effect of menu labeling on calories ordered/consumed in natural settings, menu labeling may have other impacts. Some evidence suggests that companies may be reformulating products (including decreasing calories content) in response to menu labeling regulations [113
]. Pulos and Leng [106
] reported that after seeing the results of their menu analyses, some locally owned restaurants modified portion sizes or ingredients. Some of the studies included in this meta-analysis also indicated that not all consumers or participants were aware of calorie labels [103
]. Moreover, the way that calorie information was presented was not homogeneous, clearly reported, nor described at all in some of the included studies. Among studies providing clear and full description, calorie information was placed on the menu next to food item descriptions and price in three studies [51
] and given as a separate pamphlet with the restaurant menu in Nelson et al. [104
]. The optimal method for delivering nutrition information to the consumer (i.e., font-size, color, location, etc.) is yet to be determined. Educational materials to increase awareness and explain labeling use may inform food choice and enhance labeling use [51
]. Previous nutrition knowledge was not assessed in most of the included studies, with the exception of the study by Brissette et al. [50
], which found that knowledge of the calorie Recommended Dietary Allowance was not associated with the amount of purchased calories, yet the effect of nutrition knowledge on eating behavior may manifest in other ways and is another area for future hypotheses. Other factors, as mentioned above, may also influence calories ordered and/or consumed, such as consumer preference for taste, convenience, or price. For example, taxation decreased the purchasing of more calorically dense foods in obese, but not non-obese participants in Temple et al. (2011) [108
], results that were not included in this meta-analysis, indicating that specific participant characteristics may differentially be influenced by such manipulations. Indirect impacts of menu labeling may also result; for example, menu labeling policies may lead to a shift in broader social norms to adopt healthier diets over time. Thus, menu labeling may have a potential to change dietary behavior beyond the results of this meta-analysis and other previous studies.
Consideration of dietary intake beyond calories, such as the inclusion of nutrient-dense foods and beverages—vegetables, fruits, whole grains, fat-free or low-fat milk and milk products, seafood, lean meats and poultry, eggs, beans and peas, and nuts and seeds and limiting simple carbohydrates, fat, saturated fat, and sodium is critical to understanding the efficacy of menu labeling to support dietary changes that prevent diet-related chronic diseases like diabetes, dyslipidemia, and hypertension. [114
]. Evaluation of nutrients provides evidence of potential changes in the type or quality of nutrients ordered/consumed and not only the quantity of nutrients ordered/consumed due to menu labeling changes. In our meta-analysis, significant differences in the calories ordered or consumed for carbohydrates, fat, saturated fat, and sodium were not observed after menu labeling implementation. Analysis of nutrients purchased or consumed in menu labeling interventions is of growing interest, but still few studies have included evaluation of the impact of menu labeling on the ordering/consumption behavior of nutrients. Thus, despite our results, future studies should continue to include evaluation of menu labeling on nutrients ordered/consumed to provide more robust insights into these broader aspects of menu labeling outcomes. Future studies should consider evaluating additional nutrients or dietary components such as added sugars, dietary fiber, calcium, vitamin D, potassium, and overall indicators of dietary quality such as the Healthy Eating Index in order to provide a more complete picture of dietary intake.
This meta-analysis included only studies adherent to stringent criteria, based on CC&CRG guidance and classified as “A” and “B” study designs, and to our knowledge is the first to evaluate the effect of menu labeling on calories and carbohydrates, fat, saturated fat, and sodium ordering/intake. Because few articles were found to contain evaluation of those nutrients, these results highlight the need of nutrient evaluation in future studies to draw more robust conclusions. Investigation of menu labeling effects separately for laboratory and natural settings allowed results specific to real-life environments.
Although only stringent criteria were used to grade study designs for inclusion, the diversity in study methodologies resulted in high heterogeneity. This meta-analysis did not assess what effect the posting of daily calories/nutrient requirements in addition to menu labeling had on calories and nutrients consumed and ordered. Consumer knowledge of nutrition daily requirements may affect the choice of food consumed away from home and how these choices are balanced with other food intake throughout the day. U.S. adults were included in this analysis, but specific populations, such as obese individuals or children, may react to menu-labeling differently. Finally, there exists the possibility that other unpublished studies were not included in this meta-analysis.