Hunger is known to increase food purchases, but Alison Jing Xu at the University of Minnesota and her team wanted to know if it also increased desire to buy non-food items. They asked 63 people to come to the lab with an empty stomach. Half were given a piece of cake to eat before all the volunteers were asked to examine a binder clip and decide how many they would like. Hungry participants asked for 70 percent more free clips than those who had just eaten. To find out if the same association held true for real purchases, the team had a look at the receipts of 81 customers leaving a department store that sold mostly non-food goods. Customers who were hungrier spent 64 percent more than the others. So, what is going on? When we are hungry, our stomach releases a hormone called ghrelin which acts on an area of the brain that makes people not only want to consume calories but also to seek out reward and motivation in buying other things. Jing Xu and her team suggest that consumers better feed themselves before they go shopping.