BACKGROUND In light of recent theories in behavioural economics, an intervention program with monetary incentives could be effective for helping patrons order healthy food, even if the incentive is small and less than one's perceived marginal value. METHODS In this single-arm cluster crossover trial at 26 local restaurants, a 1-week campaign offered a 50-yen (approximately 0.5 US dollars) cash-back payment to customers ordering vegetable-rich meals, while no pre-order incentives were offered during the control period. RESULTS In total, 511 respondents out of 7537 customers (6.8%), and 704 respondents out of 7826 customers (9.0%), ordered vegetable-rich meals during the control and intervention periods, respectively. During the intervention period, the covariate-adjusted proportion of vegetable-rich meal orders was 1.50 times higher (95% confidence interval [CI]: 1.29 to 1.75), which increased daily sales by 1.77 times (95% CI: 1.11 to 2.83), even when subtracting the cost of cash-back payments. Respondents who reported spending the least amount of money on eating out (used as a proxy measure for income) were the least likely to order vegetable-rich meals during the control period. However, these individuals increased their proportion of purchasing such meals during the intervention period (a 3.8 percentage point increase (95% CI: 2.82 to 4.76) among those spending the least vs a 2.1 percentage point increase (95% CI: 1.66 to 2.62) among those spending the most; P for interaction = 0.001). Similarly, irregular employees exhibited a larger increase (+ 5.2 percentage points, 95% CI: 4.54 to 5.76) than did regular workers (- 1.4, 95% CI: - 1.66 to - 1.05, P for interaction = 0.001). CONCLUSIONS A program with an immediate low-value monetary incentive could be a public health measure for reducing inequalities in making healthy food choices. TRIAL REGISTRATION UMIN Clinical Trials Registry, UMIN000022396 . Registered 21 May 2016.

中文翻译：

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低价值的财政激励计划对增加蔬菜丰富的餐厅膳食选择和减少社会经济不平等的有效性：一项集群交叉试验。

背景技术根据行为经济学的最新理论，即使奖励很小并且小于人的边际价值，带有货币奖励的干预计划也可以有效地帮助顾客订购健康食品。方法在此26家当地餐馆的单臂集群交叉试验中，为期1周的活动向订购蔬菜丰富餐点的顾客提供了50日元（约合0.5美元）的现金返还，但没有提供任何预购奖励措施。在控制期间。结果总共有7537名顾客中的511名受访者（6.8％）和7826名顾客中的704名受访者（9.0％）在控制和干预期间分别订购了富含蔬菜的餐食。在干预期间，富含蔬菜的膳食订单的经协变量调整后的比例为1。增长50倍（95％的置信区间[CI]：1.29至1.75），即使扣除现金返还的成本，每天的销售额也增加了1.77倍（95％的CI：1.11至2.83）。报告称在外出就餐上花费最少的钱（用作收入的衡量标准）的受访者在控制期内订购蔬菜含量高的餐点的可能性最小。但是，在干预期间，这些人增加了购买此类餐点的比例（增加了3.8个百分点（95％CI：2.82至4.76），而支出最少的人群则增加了2.1个百分点（95％CI：1.66至2.62）。在支出最高的人群中；互动的P = 0.001）。同样，非正规员工的增长幅度也更大（+ 5.2个百分点，95％CI：4.54至5.76），而普通工人的增长幅度更大（-1.4，95％CI：-1.66至-1.05，相互作用的P = 0.001）。结论一项具有立即低价值货币激励的计划可以是减少健康食品选择中的不平等现象的公共卫生措施。试用注册UMIN临床试验注册，UMIN000022396。2016年5月21日注册。