Consumers who take cash to the shops and leave their debit cards at home are more likely to leave junk food on the shelves, U.S. scientists have discovered.

The study carried out by Cornell University and the University at Buffalo analysed the shopping behaviour of 1,000 households. They found that supermarket trolleys had a larger proportion of junk food items when the shopper was using credit or debit cards rather than cash.

'Two factors contribute to this intriguing effect,' the authors explained. 'First, there is a correlation between unhealthiness and impulsiveness of food items: unhealthy food items tend to elicit impulsive responses.

'Second, cash payments are psychologically more painful than card payments, and this pain of payment can curb the impulsive responses to buy unhealthy food items.'

They even suggested that there may even be a connection between rising obesity levels in western countries and changing modes of payment.

相关中文：

根据美国科学家的研究，用刷卡购物的人比用现金购物的更容易购买垃圾食品，也就是说，更容易发胖啦！

根据康奈尔大学和水牛城大学对美国1000户普通家庭的调查，研究人员发现，当人们刷卡付钱的时候，购物车里垃圾食品的比率大大高于用现金购物的人。

 研究人员说：“造成这个有趣现象的原因很多，首先不健康是和对食物的冲动紧密相连的，不健康的食物种类可以引发冲动的反应；第二，使用现金付款比用信用卡付款给人心理上造成的痛苦更多，因此用现金消费引发的痛苦会抑制大家购买垃圾食品的冲动性。”

美国科学家甚至认为，造成西方人普遍肥胖的原因之一就是他们都刷卡付钱，这个方式造成了人民的肥胖——根据2008年英国的数据统计，1/4的英国人都体重超标——如果改变一下消费方式呢？

大家可以观察一下，是不是瘦人一般用现金比较多？而胖子一般都刷卡？