摘要：Objectives. We examined the effect on food purchases of adding recommended calorie intake per day or per meal to the mandated calorie information posted on chain restaurant menus. Methods. Before and after New York City implemented calorie posting on chain restaurant menus in 2008, we provided daily, per-meal, or no calorie recommendations to randomized subsets of adult lunchtime customers (n = 1121) entering 2 McDonald’s restaurants, in Manhattan and Brooklyn, and collected receipts and survey responses as they exited. In linear and logistic regressions, with adjustment for gender, race, age, and day, we tested for simple differences in calories consumed and interactions between variables. Results. Posting calorie benchmarks had no direct impact, nor did it moderate the impact of calorie labels on food purchases. The recommendation appeared to promote a slight increase in calorie intake, attributable to increased purchases of higher-calorie entrées. Conclusions. These results do not support the introduction of calorie recommendations as a means of enhancing the impact of posted calorie information or reducing the contribution of restaurant dining to the obesity epidemic. Obesity rates in the United States, having risen dramatically beginning in the 1980s, 1 began to level off about a decade ago, 2 albeit at the high rate of about one third of the population. 3 Obesity increases the risk of chronic conditions such as diabetes and heart disease, 4 accounting for an estimated 5% to 15% of annual deaths 5,6 and $150 billion in annual health care costs in the United States. 7 Such statistics have led policymakers to take a closer look at potential causes of, and opportunities for legislative response to, the obesity epidemic. Restaurant meals are a natural target for policy interventions aimed at combating obesity. They have accounted for a growing fraction of calorie intake over time, 8 and at the individual level, obesity is positively associated specifically with patronage of fast-food restaurants. These restaurants, which are especially popular with low-income individuals, who have a higher risk of obesity, encourage additional calorie consumption by promoting larger meals at minimal additional marginal cost. 9,10 Although existing regulations require such restaurants to make calorie information available to customers, few customers seek out the information. 11 To encourage use of calorie information by diners, several states and municipalities have introduced regulations that mandate posting of calorie information on the menus and menu boards of chain restaurants. 12 New York City (Amended Health Code §81.50 2007); King County, Washington State (HB 3160 2008); Philadelphia, Pennsylvania (City Council Bill 080167 2008); San Francisco, California (Ordinance No. 40–08 2009); California State (SB 1420 2008); and Oregon (HB 2726 2009) have all implemented mandatory calorie-posting regulations, and nationwide regulations will soon go into effect as part of recent health care reform legislation (Pub L No. 111-148). Existing literature on calorie labeling provides a mixed picture, at best, of its impact. Despite some promising laboratory studies, 13 repeated and well-powered tests of menu labeling in situ have not been encouraging. Although consumers’ estimates of how many calories their meals contain improve, 14 and those who report using labels tend to choose lower-calorie meals than those who report not using them, 15,16 population-wide behavior has been found to respond little if at all to calorie posting. 16–21 One commonly proposed reason for the apparent failure of menu labeling to change behavior, leading to a natural prescription for how to improve the effectiveness of such labeling, is that people lack guidelines about recommended calorie intake that could help them interpret the labels. 22 Articulating such concerns, a year after introducing mandatory calorie posting, New York City augmented the policy with a campaign publicizing daily calorie recommendations. 23 Going a step further, the mandatory calorie posting associated with national health care reform includes a requirement for restaurants to post daily recommended calories directly on menus. In the laboratory, a recommendation for daily calorie intake presented with dinner menus has been shown to reduce self-reported compensatory eating later in the evening, 24 and in a field experiment it directly reduced meal calories when presented during meal choice. 25 However, although both studies observed a direct effect of recommendations, neither found a significant interaction between calorie labeling and calorie recommendations, suggesting that the recommendation did not facilitate use of labels. Moreover, in the field study, the recommendation affected calorie intake by normal-weight restaurant patrons but had no impact on overweight diners. 25 We examined whether providing calorie recommendations altered the impact of calorie posting on the calories purchased. Specifically, we explored the effectiveness of providing 1 of 2 levels of calorie recommendation, either the recommended number of calories per meal or the recommended number of calories per day. Our study was an experimental manipulation of the presence and type of calorie recommendation, embedded in a pre–post field study of New York City’s calorie-labeling regulations on consumer food purchases at 2 McDonald’s restaurants. 21 We were interested in whether, consistent with earlier research, receiving such information at the point of purchase would affect calories purchased regardless of whether calorie information was posted or would interact with the menu labeling by aiding consumers in using the posted information. We considered not only the standard daily recommendation, but also recommended intake for the meal (lunch), in accordance with the mandate by the National School Lunch Act that school lunches provide at least one third of the daily recommended dietary allowances for key nutrients. We reasoned that meal rather than daily calorie recommendations might be more directly relatable, and hence more useful, in guiding decisions involving a single meal.
