An associate professor of preventative medicine at Rush University Medical Center has invented a device designed to help people make better food choices. The gadget fits inside vending machines and makes buyers who purchase unhealthy snacks wait 25 seconds before their selection drops. But people who choose healthier options – like peanuts or popcorn – get their selection immediately. 
Every second you wait on your snack makes you want it less. Think of it as a “time tax” along the same lines as a soda tax. Brad Appelhans, the designer of the device, says:
“We were interested in the ability to test whether time delays can nudge people to healthier choices.” 
“We’ve known for a long time that there’s an association between the delay until you receive a reward and how influential it is to your decision. The longer you have to wait for something, the less desirable it is.” 
This is because humans seek instant gratification, which often translates to sugary, fatty junk food. Weight loss takes time, for example; but a package of donuts can be ripped open and eaten immediately. Appelhans explains:
“The health benefits of making a healthy food choice generally aren’t realized for many years, whereas your choice to have a delicious donut is rewarded right away. If we can delay the junk food relative to the healthier option, we’re essentially using that principal of delayed gratification in reverse.” 
The device is dubbed “DISC,” or “Delays to Influence Snack Choices.” Inserted into a vending machine, the DISC platform delays unhealthy snacks in their drop from the top half of the machine. A message on the display window informs buyers they’ll have to wait an additional 25 seconds for their junk food. 
When a selection falls onto the DISC, a 25-second countdown is triggered on the vending machine’s display screen. At the end of those long 25 seconds, DISC drops its platform and the snack falls into the vending machine’s bay. Healthier snacks completely bypass the platform with no wait.
To qualify as a “healthier” snack, items had to meet at least 5 of the following criteria:
- Less than 250 calories
- No more than 350 mg of sodium
- No more than 10 grams of added sugars
- No trans fats
- Less than 35% of their calories from fat
- More than 1 gram of fiber per serving
- Less than 5% of the daily allowance of saturated fat per serving 
Appelhans tested DISC by placing it into three vending machines around Rush University, which has a patent pending on the device. The experiment lasted 14 months, during which over 32,000 snacks were dispensed. 
He experimented with other stuff, too, like lowering the price of healthier snacks or increasing the price of unhealthy ones. Then he sat back and watched as students broke into the machines, kicked them, and swore. 
OK, that last part was purely my imagination.
The outcome was quite positive. Appelhans presented a study at the annual meeting of the Society of Behavioral Medicine in San Diego, reporting that many people started picking healthier snacks because of DISC.
Appelhans says the delay alone resulted in a roughly 5% change in the proportion of healthier snacks that were sold – approximately the same increase in sales that he saw when he lowered the price of the healthier snacks by 25 cents or raised the price of unhealthy ones by 25 cents but did not impose a time delay.
Using the 25-cent price change in addition to the delay resulted in greater increases in healthier snack sales than the delay alone, but Appelhans says that the delay has some advantages over the lowered price.
“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.” 
The researchers would like to study the effects of time delay on food choices in other contexts as well, such as fast-food joints and online grocers. Appelhans also hopes to find a commercial partner to bring DISC to the market. Appelhans says:
“Vending machines are the biggest source of high-calorie, nutrient-poor foods in the United States, and there’s a huge need for strategies to make them healthier. We think this could have a major impact, but first we need the industry to get on board.”