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.

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估算卡路里菜单标签对美国南部一家大型饭店特许经营店购买的卡路里的影响：准实验研究。

目的评估大型连锁餐厅菜单中的卡路里标签是否与每笔交易购买的平均卡路里的变化相关。设计准实验纵向研究。从2015年4月至2018年4月，在美国南部（路易斯安那州，得克萨斯州和密西西比州）建立具有3个不同餐厅连锁店的国家级快餐公司的大型特许经营权。参与者104家带有卡路里信息的餐厅已添加至店内和直通车道标签在2017年4月发布，并在标签实施前（2015年4月至2017年4月）和标签实施后（2017年4月至2018年4月）提供每周汇总的销售数据。主要观察指标初步结果是，实施卡路里标签后，平均交易的平均水平和趋势变化与反事实（即假设干预措施未发生时干预前的趋势将持续存在）相比，采用中断的时间序列进行线性混合模型进行分析。次要结果是按项目类别（主菜，副食品和含糖饮料）分类的。亚组分析估计了由饭店人口普查区（进行人口普查的定义区域）的社会人口统计学特征所定义的阶层中的卡路里标签作用。结果该分析样本包括14 352个餐厅周。三年来，在104家餐厅中，进行了49 062 440笔交易，并购买了242 726 953件商品。标记实施后，观察到60卡路里/事务的水平降低（95％置信区间48到72；大约4％），随后增加了0.71卡路里/事务/周的趋势（95％可信区间0.51到0.92），与基线趋势无关实施后一年内。这些结果对于敏感性分析中的不同分析假设通常是可靠的。侧面的水平下降和实施后的趋势变化要比主菜或含糖甜饮料要强。中位数收入较高和较低的人口普查区的水平下降幅度相似，但低收入（卡路里/交易/周的变化为0.94，95％的置信区间为0.67至1.21）下，每笔交易的卡路里实施后趋势更高。高收入普查区（0.50，0.19至0.81）。结论在大型连锁快餐店实施卡路里标签后，观察到每笔交易购买的平均卡路里小幅下降。在一年的随访中，这种减少减少了。