vending machine choices
Diet & Nutrition

Time Delays in Vending Machines Prompt Healthier Snack Choices

Preventive medicine experts at Rush University Medical Center have discovered that delaying access to tempting high-calorie foods and snacks in vending machines potentially can shift people’s choices to purchase less desired, but healthier snack options. Results of this study were presented Friday, March 31st 2017 at the Society of Behavioral Medicine’s Annual Meeting & Scientific Sessions in San Diego, California.

A release from the medical center quotes Brad Appelhans, PhD, clinical psychologist at the Rush University Prevention Center and lead investigator of the study, as saying, “Having to wait for something makes it less desirable. Research shows that humans strongly prefer immediate gratification, and this preference influences choices and behavior in daily life. We wanted to see if we could use this preference for immediate gratification to improve people’s vending machine snack choices.Junk food is often immediately available and convenient.

The release notes that vending machines are the most prevalent source of high-calorie snacks in the U.S. There are 1.3 million snack vending machines across the U.S.

In an NIH-funded, ecological study, Appelhans and other researchers at Rush developed a new vending machine system and created a technology called the DISC system (Delays to Improve Snack Choices). The DISC vending machine system employs a “delay” bar that separates the healthier snacks from the less nutritious options.

When an individual selects a less nutritious snack, the system begins a 25-second time delay before the machine releases the snack from the vending machine.

The vending machine with the DISC vending machine system also has an LED screen, which displays the delay times for less healthy snack items, and a delivery countdown, which allows an individual to change their snack choice to a healthier option.

“This delay yielded a 2 percent to 5 percent increase in the proportion of total purchases from healthy snacks,” said Appelhans. “Also, we found that the delay did not harm total sales volume or vending revenue, which is important to vending machine operators.”

Prior vending machine interventions have focused on complete removal of unhealthy snacks or the machines altogether. However, these restriction-based strategies have proven to be undesirable, because they limit the options available and reduce the vending machine profits that schools, workplaces and other organizations count on.

The study of the DISC vending machine system looked at the following six vending machine interventions in three locations between June 2015 and August 2016:

  1. No intervention
  2. 25-second time delay on less healthy snacks
  3. 25-cent discount on healthy snacks
  4. 25-cent tax on less healthy snacks
  5. 25-second time delay on less healthy snacks and 25-cent discount on healthier snacks
  6. 25-second time delay and 25-cent tax on less healthy snacks