美国哈佛大学公共卫生学院Joshua Petimar课题组在最新研究中，分析了卡路里菜单标签对美国南部大型连锁餐厅购买卡路里的影响。相关论文于2019年10月30日发表于国际顶尖学术期刊《英国医学杂志》。

2017年4月，美国南部三家拥有国营快餐公司大型特许经营权的连锁大饭店的104家餐厅将卡路里信息添加到菜单标签中，研究组对这些餐厅实施标签前（2015年4月至2017年4月）和标签后（2017年4月至2018年4月）每周的销售数据进行汇总分析。

研究组共分析了14352个餐厅周。三年多来，104家餐厅共发生了49062440笔交易，消费者共购买了242726953份菜品。实施卡路里标签后，研究组观察到每笔交易减少了60卡路里，在这之后的一年内，不考虑基线趋势，每周每笔交易又增长0.71卡路里。与主菜和糖类饮料相比，配菜在实施标签后卡路里降低的趋势更明显。中等较高收入和较低收入普查地区之间的卡路里减少程度相差不大，但低收入普查地区在实施标签后的每笔交易的卡路里趋势却显著高于高收入普查地区。

总之，在大型连锁快餐店实施卡路里标签后，每笔交易的平均卡路里购买量略有减少。但在一年的随访中，减少程度略有反弹。

附：英文原文

Title: Estimating the effect of calorie menu labeling on calories purchased in a large restaurant franchise in the southern United States: quasi-experimental study

Author: Joshua Petimar, Fang Zhang, Lauren P Cleveland, Denise Simon, Steven L Gortmaker, Michele Polacsek, Sara N Bleich, Eric B Rimm, Christina A Roberto, Jason P Block

Issue&Volume: 2019/10/30

Abstract: 

Objective To evaluate whether calorie labeling of menus in large restaurant chains was associated with a change in mean calories purchased per transaction.

Design Quasi-experimental longitudinal study.

Setting Large franchise of a national fast food company with three different restaurant chains located in the southern United States (Louisiana, Texas, and Mississippi) from April 2015 until April 2018.

Participants 104 restaurants with calorie information added to in-store and drive-thru menus in April 2017 and with weekly aggregated sales data during the pre-labeling (April 2015 to April 2017) and post-labeling (April 2017 to April 2018) implementation period.

Main outcome measures Primary outcome was the overall level and trend changes in mean purchased calories per transaction after implementation of calorie labeling compared with the counterfactual (ie, assumption that the pre-intervention trend would have persisted had the intervention not occurred) using interrupted time series analyses with linear mixed models. Secondary outcomes were by item category (entrees, sides, and sugar sweetened beverages). Subgroup analyses estimated the effect of calorie labeling in stratums defined by the sociodemographic characteristics of restaurant census tracts (defined region for taking census).

Results The analytic sample comprised 14 352 restaurant weeks. Over three years and among 104 restaurants, 49 062 440 transactions took place and 242 726 953 items were purchased. After labeling implementation, a level decrease was observed of 60 calories/transaction (95% confidence interval 48 to 72; about 4%), followed by an increasing trend of 0.71 calories/transaction/week (95% confidence interval 0.51 to 0.92) independent of the baseline trend over the year after implementation. These results were generally robust to different analytic assumptions in sensitivity analyses. The level decrease and post-implementation trend change were stronger for sides than for entrees or sugar sweetened beverages. The level decrease was similar between census tracts with higher and lower median income, but the post-implementation trend in calories per transaction was higher in low income (change in calories/transaction/week 0.94, 95% confidence interval 0.67 to 1.21) than in high income census tracts (0.50, 0.19 to 0.81).

Conclusions A small decrease in mean calories purchased per transaction was observed after implementation of calorie labeling in a large franchise of fast food restaurants. This reduction diminished over one year of follow-up.

DOI: 10.1136/bmj.l5837

Source: https://www.bmj.com/content/367/bmj.l5837