What Your Shopping Bag Has to Do With Your Expanding Waistline

Here’s some food for thought: Reusable shopping bags may be good for the environment, but they could be bad for your waistline.

A new study published in the Journal of Marketing found that shoppers who use reusable grocery bags are more likely to fill their cart with cookies, potato chips and other treats.

“Grocery store shoppers who bring their own bags are more likely to purchase organic produce and other healthy food,” write study authors Bryan Bollinger, assistant professor of marketing at Duke University, and Uma Karmarkar, assistant professor of business administration at Harvard Business School. “But those same shoppers often feel virtuous, because they are acting in an environmentally responsible way. That feeling easily persuades them that, because they are being good to the environment, they should treat themselves to cookies or potato chips or some other product with lots of fat, salt or sugar.”

The study refers to the “licensing effect,” a psychological term for when people who feel virtuous for doing something good (using a reusable bag) then feel entitled to do something self-indulgent (purchase junk food).

The study is based on two years of research at a California supermarket, where the authors tracked the same shoppers who sometimes used a reusable bag and other times did not, and then compared their shopping trip items. Other data came from online participants who were randomly assigned one of two situations: bringing their own reusable bag or not using their own bag.

On average, the probability of purchasing organic produce jumped 13 percent if a shopper brought a reusable bag. But their chance of purchasing a junk food item also rose by about 7 percent when they had a reusable bag.

“In short, bringing your own bags changes the way you shop,” the authors write. “Our findings thus have important implications for grocery store managers. In stores where reusable bags are popular, marketing organic or sustainably farmed foods as indulgences could increase the sales of those items.”

Do you use reusable shopping bags? Do the findings of this study ring true for you? Share your comments below or on our Facebook page.