Waiting at Vending Machines May Help You Make Healthier Choices


When you’re hungry for a snack, there are few things more annoying than waiting in line to buy a tasty treat from a vending machine. So you can imagine how frustrating it must be to try to purchase a snack from one of Bradley Appelhans’ experimental vending machines, which make you wait 25 seconds before it dispenses an unhealthy treat.

Appelhans, an associate professor of Preventative Medicine at Chicago’s Rush Medical College, presented his study in San Diego at the annual meeting of the Society of Behavioral Medicine.

Bradley Appelhans stands next to a vending machine equipped with his DISC add-on device. Credit: Rush University Medical Center

He created a sort of “time tax,” where theoretically every second you wait the less likely you’ll want the unhealthy snack. The concept is similar to taxes on soda, which ultimately hopes to deter you from purchasing a sugary drink.

“We were interested in the ability to test whether time delays can nudge people to healthier choices,” Appelhans told NPR.

Appelhans created the “Delays to Influence Snack Choice” device, or DISC, to test his theory that forcing people to wait will help them make better decisions about what food they want. The DISC is a device added to a vending machine that sorts unhealthy snacks from the healthy ones; it also forces the consumer to wait 25 seconds for an unhealthy snack.

Healthy snacks had to meet five out of seven criteria, some of which included being 250 calories or less, having 350 mg of sodium, and having 10 mg of added sugar per serving. For example, popcorn and peanuts were considered healthy.

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The device was added to vending machines on the Rush University campus for several months. For each month the DISC was in a vending machine, Appelhans tried different price conditions by either lowering the price of healthier snacks or raising the price on the less healthy snacks. After about a month, people started picking the healthier snacks.

Vending machines like this one could be found on the Rush campus. Credit: Brad Appelhans via WFDD

There was about a five percent change in the amount of people who bought healthy snacks when the time delay was implemented. There was about the same increase in sales when the price of healthy snacks dropped by 25 cents, with no time delay on the unhealthy snacks.

Although this was not a huge difference, “if you are to extrapolate this out across 1 million vending machines and over time, it could add up to something meaningful,” Appelhans explained.

Vending machines, according to the study’s authors, are the largest source of high-calorie snacks in the United States, with nearly 1.3 million snack vending machines around the country.

Previous studies have shown that healthy food interventions, like removing unhealthy food temptations altogether, hurt the vending machine’s profits that are relied on by the institution or organization it’s located in.

“Unlike the discount, the delays didn’t harm the overall revenues of the machine. Places want people to have more nutrition, but they don’t want to lose revenue. So the time delay might be a nice way to have it both ways,” Appelhans said.

Related: These Late Night Snacks Won’t Leave You Feeling Guilty