Discussion

The findings of the present study indicate that higher-calorie combination meals contain significantly more calories per dollar compared with default combination meals, with an average difference of 71 kJ (17 kcal)/dollar for breakfast combination meals and 130 kJ (31 kcal)/dollar for lunch/dinner combination meals. There was no significant difference for children’s meals, a finding that may be attributable to the small sample size (thirty-four meals). Together, our findings suggest there is a strong financial incentive for price-conscious consumers to upsize their combination meals. This is particularly problematic in light of our results showing that these additional calories are also accompanied by considerable increases in saturated fat, sodium and sugar. Since Americans spend more than 50 % of their food dollars away from home⁽²²⁾, the low price of additional calories in restaurants may be an important factor driving overeating and weight gain in the USA.

The price incentive structure documented in the present study capitalizes on one of the key drivers of consumer behaviour in the USA: value for money⁽Reference Glanz, Basil and Maibach⁶⁾. Marketing research suggests that value pricing is attractive to consumers and entices them to spend more than they would with proportional pricing⁽Reference Haws and Liu^23, Reference Haws and Winterich²⁴⁾ because a larger quantity at a discounted price is perceived as a bigger ‘bang for their buck’⁽Reference Haws and Winterich²⁴⁾. Evidence also suggests that low-income individuals are more responsive to price changes, which may increase susceptibility to point-of-sale price promotions in restaurants⁽Reference Andreyeva, Long and Brownell²⁵⁾. Notably, while consumers have a price incentive to upsize orders in combination meals, restaurants do not appear to incentivize healthy modifications (e.g. replacing a sugary beverage with a zero-calorie alternative, eliminating a high-calorie condiment or replacing fries with a healthy side option like apple slices does not reduce the price of the meal). A systematic review on the price elasticity of demand for food found that away-from-home food was the most responsive category to price changes, suggesting that interventions manipulating restaurant prices could effectively encourage people to make healthier food choices⁽Reference Andreyeva, Long and Brownell^25, Reference Deliens, Deforche and Annemans²⁶⁾. However, the evidence is weak on whether replacing value pricing of fast-food items with proportional pricing leads consumers to purchase smaller serving sizes⁽Reference Vermeer, Alting and Steenhuis^27–Reference Gollust, Tang and Runge²⁹⁾.

Alternative pricing approaches that have been proposed in other settings or applied to other products could be translated to restaurant food. For example, policy makers could consider banning ‘multi-buy’ (e.g. two $US 3 items for a discounted price of $US 5) quantity-based price promotions in restaurants, as the UK previously implemented for alcohol and is currently considering for unhealthy items in supermarkets^(30, Reference Nakamura, Suhrcke and Pechey³¹⁾. Similarly, governments may consider a form of ‘minimum unit pricing’ (as has been done for alcohol in many countries) wherein a minimum price is set for the sale of unhealthy food⁽Reference Boniface, Scannell and Marlow³²⁾. Because the effectiveness of these policies has not yet been evaluated in the context of restaurant food, this is an area that is ripe for implementing and evaluating innovative interventions that could potentially be useful as policy options.

In addition to price incentives, other policy approaches such as healthy defaults, portion-size restrictions and calorie labelling have been proposed in the US restaurant environment in recent years and may be used to incentivize customers to make healthier choices. In particular, governmental policy that regulates what restaurants can serve may be effective, because this does not rely on individual behaviour change. One increasingly popular area is offering healthier default meal options given individuals’ strong tendency to stick with the status quo⁽Reference Blumenthal and Volpp^33, Reference Loewenstein, Brennan and Volpp³⁴⁾. For example, some local laws in the USA require restaurants to offer only healthy beverages instead of sugary drinks as the default beverage with children’s meals (e.g. New York City’s Healthy Kids Meals bill)⁽³⁵⁾. Another strategy is to reduce portion sizes in restaurants either by making default serving sizes smaller or reducing the availability of larger portion sizes⁽Reference Marteau, Hollands and Shemilt³⁶⁾. For example, New York City’s Sugary Drinks Portion Cap Rule, which was passed in 2013 and later repealed, prohibited the sale of sugary drinks larger than 473 ml (16 fl. oz) in restaurants and similar settings. Menu labelling is another policy option to promote healthier combination meal choices in restaurants. Currently, chain restaurants in the USA with more than twenty outlets are required to post calories on their menus, but these caloric values are provided as a range (e.g. 1883–2929 kJ (450–700 kcal)) for combination meals⁽³⁷⁾. Since calorie ranges may have little or no meaning for most customers, one option to promote healthier restaurant choices may be to require restaurants to provide specific calorie information for the default or most frequently ordered version, in addition to the lower- and higher-calorie versions reflected by the calorie range. However, before such a policy could be implemented, research is needed to understand potential unintended consequences, such as whether low-income customers use calorie information to maximize calories per dollar.

The present study identified considerable variation in the difference in calories per dollar between default and higher-calorie meals across the ten restaurants included in the sample. Subway (the fast-food restaurant chain with the largest number of outlets in the USA)⁽³⁸⁾ provided the biggest economic incentive to maximize calories by ordering a higher-calorie meal, while Dunkin’ Donuts provided almost no financial incentive to upsize. Differences across restaurants may be attributed to differences in the price of the respective components driving additional calories present in higher-calorie meal versions. For example, additional calories at sandwich restaurants (e.g. Subway) are largely driven by increases in sandwich size (a change that increases both the calories and price of a meal) and additional toppings (a change that increases the calories, but not the price of a meal). In contrast, additional calories at a breakfast restaurant (e.g. Dunkin’ Donuts) are primarily driven by substitution of the beverage from coffee to orange juice (a change that is accompanied by a modest price increase that mostly compensates for the increase in calories).

The present study has several limitations. First, the analysis did not include sales or consumption data and therefore it is not known which combination meal version consumers tend to purchase. While we utilized a detailed codebook to create the combination meal options, it is possible that these meals do not reflect the most popular default and higher-calorie consumer choices. For example, two restaurants (Chick-Fil-A and Wendy’s) did not explicitly advertise a dipping sauce to be included in their default meals, so we chose to use the dipping sauce with the closest number of calories to the mean calories of all available dipping sauces. While these types of rules were necessary to ensure consistency across all restaurants, they may not always reflect the meals most commonly ordered by consumers. Second, the generalizability of the study is limited because it included only ten large fast-food chain restaurants in the USA (of which four of ten primarily serve sandwiches), with price data collected from fifteen cities. Finally, nutrition data are limited to nutrients included in the MenuStat database so we could not comprehensively assess nutritional quality (e.g. vitamins and minerals). Despite these limitations, the study has a number of strengths including the examination of combination meals (instead of individual menu items), the comparison of three meal types (breakfast, lunch/dinner and children’s) and the collection of standardized fast-food restaurant price data from fifteen large cities.

To better understand the relationship between price incentives and consumer behaviour, future research is needed to document current consumer purchasing patterns of combination meals at fast-food restaurants in the USA. For example, researchers may examine purchasing patterns using meal receipts collected through customer intercept surveys outside fast-food restaurants or through collaboration with industry to purchase scanner data. Sales information is critical to identify precise consumer meal customization patterns and the frequency at which customers upsize their combination meals in fast-food restaurants. It is of particular interest to examine whether low-income individuals are more likely to upsize their combination meals and what the primary motivators to upsize are (e.g. splitting food into multiple meals, better value). There is also a need to assess whether proportional pricing could encourage lower-calorie orders and to evaluate other strategies aimed at making lower-calorie choices in restaurants easier for consumers. These strategies could first be evaluated in experimental settings (e.g. an online simulated restaurant environment in which study participants order from menus with different pricing strategies) or in real-world retail settings through collaboration with fast-food restaurants.