1 Department of Applied Economics and Management, Cornell University, Ithaca, NY, USA.
Public Health Nutr. 2013 Dec;16(12):2281-8. doi: 10.1017/S1368980013001468. Epub 2013 May 28.
To examine whether requiring children to place fruits and vegetables on their lunch trays increases consumption of these items.
Observational study that exploited naturally occurring variation between two school districts and a pre–post observational study at schools that changed their lunch policy mid-year.
Fifteen elementary schools from two school districts, one requiring students to place a fruit or vegetable on their tray and one that does not. In addition, three schools that implemented a default option part way through the school year.
Students at eighteen elementary schools (41 374 child-day observations) across the two experiments.
Requiring that fruits and vegetables be placed on each child's tray increased the fraction of children who ate a serving of fruits or vegetables by 8 percentage points (P < 0·01) but led to an extra 0·7 servings being thrown away per lunch served (P < 0·01). The default option approach cost $US 1·72 to get one additional child to eat one serving of fruits and vegetables for 1 d. However, when default options were combined with a small rewards programme the efficacy of both interventions increased.
A default option, as a stand-alone programme, had only a limited impact on fruit and vegetable consumption but was much less cost-effective than other approaches. Schools requiring children to take fruits and vegetables with their lunch might consider adopting additional interventions to ensure that the additional items served do not end up being thrown away.
研究要求儿童将水果和蔬菜放在午餐托盘上是否会增加这些食物的摄入量。
利用两个学区之间的自然差异进行观察性研究,并对午餐政策在学年中途发生变化的学校进行了预-后观察性研究。
两个学区的 15 所小学,其中一个要求学生在托盘上放置水果或蔬菜,另一个则不要求。此外,还有三所学校在学年中途实施了默认选项。
来自两个实验的 18 所小学的学生(41374 个儿童日观察值)。
要求每个孩子的托盘上都要放水果和蔬菜,这使得吃一份水果或蔬菜的孩子比例增加了 8 个百分点(P<0·01),但每顿午餐额外扔掉了 0·7 份(P<0·01)。默认选项方法每让一个孩子额外吃一份水果和蔬菜 1 天需要花费 1.72 美元。然而,当默认选项与小额奖励计划相结合时,两种干预措施的效果都有所提高。
作为一个独立的项目,默认选项对水果和蔬菜的摄入量只有有限的影响,但比其他方法的成本效益低得多。要求儿童带水果和蔬菜吃午餐的学校可以考虑采取额外的干预措施,以确保额外提供的食物不会被扔掉。