The Big, Bad, Belly-Bloating Consequence of Recyclable Grocery Bags


While reusable shopping bags are good for the environment, surprising new research has found they can be bad for your waistline. (Photo: Getty Images)

People have been encouraged for years to use environmentally friendly
reusable shopping bags at the grocery store. Some major cities have even banned stores from handing out single-use bags for free to customers, and California passed a law last year that will prohibit the practice.

But while reusable shopping bags are good for the environment, surprising new research has found they can be bad for your waistline.

A new series of studies published in the Journal of Marketing found that people who bring their own reusable shopping bags are more likely to buy junk food at the grocery store than when they don’t BYOB.

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Researchers analyzed more than two million trips to a California supermarket to find out whether shopping bags influenced what a person purchased. They discovered that when people brought their own bags, they were more likely to buy organic (good!) and purchase chips, candy, cookies, and ice cream (bad!).

Scientists attribute the organic purchases to a “priming effect,” in which you match your behavior (shopping organic) with a previous action (bringing an environmentally friendly bag). The junk food aspect is due to a “licensing effect,” where you’ve done something good and want to reward yourself. The licensing effect can happen in other areas of life — some people will splurge on dessert after a run; others may treat themselves after giving to charity.

“We anticipated that these effects were there but the fact that we did find them was surprising since bringing a bag is such a subtle thing,” study co-author Bryan Bollinger, PhD, an assistant professor of marketing at Duke University’s Fuqua School of Business, tells Yahoo Health.

While some people reported that they consciously reward themselves for environmentally friendly shopping behavior, Bollinger suspects that the majority of shoppers aren’t aware that the effect is in place.

Related: 7 Health Foods You Should Stop Throwing Away

There were some caveats to the findings: People who were told they had to bring a reusable shopping bag (vs. doing it on their own) were no more likely to buy junk food than when they used disposable plastic bags. “You have to attribute the act of bringing a bag to your own virtuous behavior to experience the effect,” explains Bollinger.

Parents didn’t fall victim to the junk food trap either, Bollinger says, adding, “we suspect that when you have kids, you have more pressing things to consider when you’re shopping.”

According to psychologist Paul Coleman, PsyD, the side effects that come with using a reusable bag are just human nature. “Most people have mixed feelings about issues,” he tells Yahoo Health. “If I’m somebody who wants to be green and do the right thing, there’s another part of me that probably says at times that I just want to splurge and have fun.”

Noticed you’ve fallen victim to the junk food trap? Don’t chuck your reusable shopping bag. Licensed clinical psychologist Simon Rego, PsyD, director of psychology training at New York’s Montefiore Medical Center/Albert Einstein College of Medicine, tells Yahoo Health that awareness can help break the cycle.

Related: Scientists: Junk Food Causes A Drug-Like Addiction

Still struggling? Force yourself to read the labels on junk food you’re considering. “By explicitly considering negative consequences of our actions, we stand a better chance of altering them,” says Rego.

However, it might take time to fully ditch the bad habit, since Coleman says it typically takes up to 30 repetitions to change a behavior.

In the meantime, maybe steer clear of the junk food aisle.

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