Sure, you already know the adage an apple a day keeps the doctor away. And we’ve heard time and time again that you shouldn’t go grocery shopping on an empty stomach, lest you fill your cart with impulsive sweet treats. But what happens when you combine the two? Researchers at Cornell University found that eating an apple before grocery shopping led people to buy 25% more fruits and vegetables than those who didn’t.

Aner Tal, PhD, and Brian Wansink, PhD, researchers at Cornell’s Food and Brand Lab, wanted to test their theory that healthy snacks prime shoppers to purchase healthier foods. In their first test, they randomly gave 120 shoppers either an apple sample, a cookie sample, or no sample before they hit the supermarket, and then tracked their purchases. People who had an apple sample bought 28% more fruits and veggies than those who ate a cookie, and 25% more than participants who went snack-free.

“What this teaches us,” Tal said in a press release, “is that having a small healthy snack before shopping can put us in a healthier mindset and steer us towards making better food choices.”

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In a second test, Tal and Wansink again fed 56 participants either an apple or cookie sample, and then had them choose between 20 pairs of items as if they were grocery shopping online: one low-calorie and one high-calorie. Interestingly, a version of the “health halo” effect worked here as well: people who ate apples first chose more low-calorie foods than people who had cookies.

In their final test, the researchers gave shoppers the same kind of chocolate milk but with different labels. Group one drank “rich, indulgent chocolate milk;” group two had “healthy, wholesome chocolate milk.” A third group had no milk. Again, those who knocked back the “healthy” chocolate milk made healthier virtual food purchases. This test suggested that a food sample doesn't actually have to be healthy for it to positively affect your shopping choices—you just have to think it's healthy. The researchers call that "perceived healthfulness."

It's unclear whether you can actively "trick" yourself into shopping healthier by purposely eating an apple (or something else that claims to be wholesome), but if it could help you make smarter choices, then it's definitely worth trying.

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