Stay off the coffee to avoid impulse buying

YOU should never go shopping on an empty stomach, the old adage states, and scientists believe you should also avoid going to the shops if you have just had a coffee.

Caffeine increases the likelihood of “impulse buying” where superfluous goods are added to a basket despite not being on the shopping list, a study has found.

An international project led by the University of South Florida found that caffeine affects what shoppers buy and how much they spend.

Researchers ran three experiments in large retail stores with coffee bars near their entrances. Their findings showed that shoppers who drank a cup of complimentary caffeinated coffee before roaming the stores spent about 50 per cent more money and bought nearly 30 per cent more items than those who drank decaffeinated coffee or water.

Dipayan Biswas, a professor at the university and the lead author, said: “Caffeine, as a powerful stimulant, releases dopamine in the brain, which excites the mind and the body. This leads to a higher energetic state, which in turn enhances impulsivity and decreases self-control.

“As a result, caffeine intake leads to shopping impulsivity in terms of higher number of items purchased and greater spending.”

The experiments involved setting up espresso machines at stores in France and Spain. On entry, more than 300 shoppers were provided a complimentary drink, with about half offered coffee containing 100mg of caffeine and the others decaf or water.

The findings, published in the Journal of Marketing, showed caffeine also affected the types of items bought. Those who drank caffeinated coffee bought more nonessential items than the other shoppers, such as scented candles and fragrances.

Prof Biswas said: “Consumers trying to control impulsive spending should avoid consuming caffeinated beverages before shopping.”