Reducing the price of healthy foods could land more whole grains, carrots and bananas in shopping carts, even months after the discounts are removed, according to a new study.

As rates of obesity continue to rise in much of the developed world, so does the urgency to improve people's food choices. Ni Mhurchu and her team conducted a six-month trial across eight New Zealand supermarkets to determine the effects of two strategies: price discounts and nutrition education.

A total of 1,104 shoppers were randomized to receive a price discount on healthy foods, tailored nutrition education, a combination of the two or no intervention. Healthy foods, as recognized by New Zealand's Heart Foundation, were 12.5 percent cheaper for those randomized to receive discounts. Participants assigned to nutrition education received monthly packages of food-group-specific information, which were tailored to their shopping history. Handheld barcode scanners recorded all supermarket purchases.

According to a report in the American Journal of Clinical Nutrition, after six months of intervention, participants receiving price discounts bought approximately 1.7 more pounds （790 grams） of healthy food per week compared with those not randomized to pay the lower prices.

This was an 11 percent increase from purchases made prior to the study and included just over a pound （480 grams） more fruits and vegetables per week, or about six servings. The total difference dropped to around 0.8 pounds （380 grams）, but remained significant, six months after the study was over. No consistent differences were found between the groups in the amounts of purchased saturated fat or other nutrients.

The fact that nutrition education was unsuccessful in improving food choices initially surprised Ni Mhurchu, especially since previous research had shown positive effects. Most of those studies, however, used self-report rather than the more objective supermarket sales data. Still, she said, her study participants were generally more informed and interested in healthy eating than average individuals, which could have masked education's true impact.

一项新的研究显示，健康食品降价行为会促使消费者购买更多粗粮、胡萝卜以及香蕉等产品。该研究表明，这种趋势甚至持续到打折期过后数月。

随着肥胖问题在许多发达国家愈演愈烈，改善人们对于食物的选择也成为迫切需要完成的课题。

Ni Mhurchu 及其团队在新西兰的八家超市中进行了长达六个月的追踪实验，以此评价两种不同策略的效应：降价出售与营养教育。

共有1104名消费者参与此项调查。他们被随机分配为四组：健康食品降价；接受特定的营养教育；两者兼而有之；以及无干预行为。在该实验中，健康食品（根据新西兰心脏组织的定义标准）的折扣价为原价的77.5%.而参加营养教育的消费者，根据各自不同的购物历史，每月都会收到详细的分类食物资料。期间所有超市的消费信息都经条形码扫描记录。

《美国临床营养学杂志》的一份报告中称，经过六个月的干预实验，与其他组相比，接受降价的消费者购买的健康食品平均每周多出约1.7磅（即790克）.这比研究之前增加了11%,其中包括水果和蔬菜的周购买量提高了一磅（即480克）,大约是六人份的餐量。

此项研究结束6个月后，该数据虽然降低至0.8磅（约380克）,但仍然有着深远的意义。各组在饱和脂肪等其他营养成分的消费中没有出现相应的不同。

由于此前有研究曾经证实营养教育在人们改善食物选择方面有着积极作用，Ni Mhurchu 完全没有料到营养教育策略在该实验中竟然没有成功。然而，之前的大部分研究都是采用自身评定的方式，而超市的销售数据则显得更为客观。Ni Mhurchu 认为，此次实验参与者比一般人更加了解和关注健康饮食，也许这一点恰恰隐藏着教育的真正意义。