If you find yourself getting hungry and tired around 3:00 in the afternoon and wonder what healthy snack you can eat to feel energized, grab a handful of blueberries.

Researchers at Tufts University fed elderly rats blueberry juice and discovered they were more coordinated, energetic and smarter than other older rats that didn’t get blueberry juice. Scientists are now trying to figure out what’s in the blueberry that improves motor coordination, while increasing mental and physical energy.

In the meantime, the results are great and they’re a delicious, power-packed, low-calorie snack!