Just in time for National Popcorn Day, a new study says that people in what's now Peru were eating the snack 2,000 years earlier than thought.

Coastal peoples were preparing corn-based foods up to 6,700 years ago, according to analysis of ancient corncobs, husks, tassels, and stalks recently unearthed at the Paredones and Huaca Prieta archaeological sites on Peru's northern coast.

Previously, evidence of corn as a food before about 5,000 years ago had mostly come from what are called microfossils—microscopic remains too tiny to offer much information.

But the newfound corn remains revealed a lot, via radiocarbon dating and other tests. For instance, the oldest cobs can be identified as popcorn, said study co-author Dolores Piperno, curator of New World archaeology at the National Museum of Natural History in Washington, D.C., and emerita staff scientist at the Smithsonian Tropical Research Institute in Panama....