Sweet potatoes might have played a big role.

STONES, BONES, AND WRECKS
Archaeologists in Luxor discovered the cache in 2014 while excavating a temple dedicated to Egyptian creator god Ptah.
"We couldn't believe our eyes."
Researchers located the UB II-type dive boat—a smaller submarine that typically plagued coastal waters—off the coast of Belgium, around 82 to 98 feet below the North Sea.
It's being hailed as the most important mosaic of its kind discovered in Great Britain in more than 50 years.
Just like the English Bard, Tang died in 1616, and he also penned dramatic works and romances.
File drinking Italian wine under "ancient tradition." Really, really ancient.
The currency, which dates from 253 CE to 274 CE, consists of bronze and a small amount of silver.
They want to learn what happens to salted beef and beer at sea—and more about the grub's nutritional value.
The find could help experts learn more about how farming developed in Europe during the Bronze Age.
The National Museum of Chinese Writing will pay about $15,000 for each unknown character translated, and $7500 for a disputed character’s definitive meaning.
"I just knew it was not something that you usually find."
They were perfectly preserved down to their 1940s attire.