Vending machines contribute to growing levels of obesity. They typically contain energy dense, high fat snacks and attempts at persuading consumers to switch to healthier snacks sold within the same machine have had limited success. This study explored the health benefits and cost effectiveness of the complete replacement of regular snacks with healthy items. Two vending machines were manipulated in a 6-month trial, with a healthy and regular range of products alternated between the two machines every fortnight. Healthy vending resulted in a 61% drop in calories sold relative to regular vending, significant with time and product range as random factors. There was no evidence of compensatory behaviour from nearby shop sales nor in multi-item purchases from vending machines. The impact on profit was less clear. Sales dropped by 30% during healthy vending but variability across product range meant that the change was not significant. Overall our results demonstrate that complete healthy vending can be introduced in hospitals without a catastrophic loss in sales nor compensatory behaviours that offset the public health gains of consuming healthier products.

自动贩卖机助长了肥胖。它们通常包含能量密集，高脂肪的零食，试图说服消费者改用同一台机器出售的健康零食的尝试取得了有限的成功。这项研究探讨了用健康食品完全替代常规零食的健康益处和成本效益。在为期6个月的试用期内，对两台自动售货机进行了操作，每两周在两台自动售货机之间交替更换一批正常且健康的产品。健康的自动售货机导致与常规自动售货机相比，售出的卡路里减少了61％，对于时间和产品范围作为随机因素而言，意义重大。没有证据表明附近商店的销售有补偿行为，也没有从自动售货机购买多件商品的证据。对利润的影响尚不清楚。在健康的自动售货期间，销售额下降了30％，但整个产品系列之间的差异性意味着变化并不明显。总体而言，我们的结果表明，可以在医院中引入完全健康的自动售货，而不会造成灾难性的销售损失或补偿行为，这些行为不会抵消食用更健康产品的公共健康收益。