Green Bags Linked to Junk Food Shopping

Green bag screenshot 2
  • Article by Roland Bleyer
  • March 27, 2015 at 10:30 AM

Reusable shopping bags may be good for the environment, but new research suggests they can actually be bad for our health.

A joint study from Harvard Business School and Duke University’s Fuqua School of Business found that people are more likely to buy junk food when they shop with these “green” bags. Using loyalty card data for thousands of Californian shoppers, researchers Uma Karmarkar (Harvard) and Bryan Bollinger (Duke) were able to analyse spending habits to discover the interesting trend.

Their findings also showed clear differences between shopping habits when someone brought their own bags and when they used store provided bags, with an increase in both organic food and junk food when reusable bags were on hand.

“It was clear that shoppers who brought their own bags were more likely to replace nonorganic versions of goods like milk with organic versions. So one green action led to another,” Professor Uma Karmarkar says in an interview with the Harvard Business Review.

“But those same people were also more likely to buy foods like ice cream, chips, candy bars, and cookies. They weren’t replacing other items with junk food, as they did with organic food. They were just adding it to their carts.”

Professor Karmarkar says that this kind of behaviour is known as “licensing” in consumer psychology. Basically it is doing one good thing, then “rewarding” yourself through something else.

“If I behave well in one situation, I give myself license to misbehave in another, unrelated situation,” she explains.

“Similar research has also been done on health decisions. I get a Diet Coke; I treat myself to a hamburger. In this case bringing a bag makes you think you’re environmentally friendly, so you get some ice cream. You feel you’ve earned it.”

While in some cases licensing is a conscious pattern (ie “I’ve done a big workout so now I’m going to have a nice meal”), Professor Karmarkar says that doesn’t seem to be the case with green bags. Instead, shoppers seem unconscious of the trend towards junk food when they are using their own bags.

“I don’t think people are actively thinking, ‘I’m using reusable bags, so I will get some doughnuts’,” she says.

Fortunately, awareness of this correlation between reusable bags and junk food is likely to make a difference to how people shop. So knowing that there is a tendency to “reward” for being environmentally friendly at the supermarket means you have a chance to make smarter shopping choices whenever you shop.

Images: Green bags on Google Image, source: screenshot; customers at a supermarket, source: Wikimedia Commons.

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